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                     [APPLEBY SPURLING & KEMPE LETTERHEAD]

                                                                     EXHIBIT 5.1

Trenwick Group Ltd.
Continental Building                                              23 August 2000
25 Church Street
Hamilton HM 12
Bermuda

Ladies and Gentlemen:

We have acted as legal counsel in Bermuda to Trenwick Group Ltd., a company
organised under the laws of Bermuda (the "Company") and this opinion as to
Bermuda law is addressed to you in connection with the registration under the
Securities Act of 1933, as amended, of the United States (the "Securities Act"),
by the Company of the Company's (i) 36,743,467 common shares, US$0.10 per share
(the "Shares"), and (ii) related Series A First Preference Share Purchase Rights
(the "Rights") (collectively, the "Securities"), issuable in connection with the
transactions contemplated by the Business Combination Agreement (as defined
below). The documents include:

 (i) The Amended and Restated Agreement, Schemes of Arrangement and Plan of
     Reorganization, dated as of 20 March 2000 and amended as of 28 June 2000
     (the "Business Combination Agreement"), by and among LaSalle Re Holdings
     Limited ("LaSalle Re Holdings"), LaSalle Re Limited ("LaSalle Re"),
     Trenwick Group Inc. ("Trenwick") and the Company (formerly known as Gowin
     Holdings International Limited).

 (ii) The Joint Proxy Statement/Prospectus dated 22 August 2000 (the "Joint
      Proxy Statement/Prospectus") of Trenwick, LaSalle Re Holdings and LaSalle
      Re as filed with the Securities and Exchange Commission, Washington D.C.
      (the "SEC").

(iii) The registration statement on Form S-4 of the Company relating to the
      Securities to be filed with the SEC (the "Registration Statement").

(The Business Combination Agreement, the Joint Proxy Statement/Prospectus and
the Registration Statement are hereinafter collectively referred to as the
"Subject Agreements".)

For the purposes of this opinion we have examined and relied upon the documents
listed in the Schedule to this opinion (the "Documents"). Unless otherwise
defined herein, capitalised terms have the meanings assigned to them in the
Joint Proxy Statement/Prospectus.

ASSUMPTIONS

In stating our opinion we have assumed:

(a) the authenticity, accuracy and completeness of all Documents submitted to us
    as originals and the conformity to authentic original Documents of all
    Documents submitted to us as certified, conformed, notarised, faxed or
    photostatic copies;

(b) the genuineness of all signatures on the Documents;

(c) the authority, capacity and power of each of the persons signing the
    Documents (other than the Company in respect of the Subject Agreements);

(d) that any representation, warranty or statement of fact or law, other than as
    to the laws of Bermuda, made in any of the Documents is true, accurate and
    complete;

(e) that the Subject Agreements constitute the legal, valid and binding
    obligations of each of the parties thereto, other than the Company, under
    the laws of its jurisdiction of incorporation or its jurisdiction of
    formation;
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(f) that the Subject Agreements have been or will be validly authorised,
    executed and delivered by each of the parties thereto, other than the
    Company, and the performance thereof is within the capacity and powers of
    each such party thereto, and that each such party to which the Company
    purportedly delivered any of the Subject Agreements to date has actually
    received and accepted delivery of such Subject Agreements;

(g) that the Subject Agreements will effect, and will constitute legal, valid
    and binding obligations of each of the parties thereto, other than the
    Company, enforceable in accordance with their terms, under the laws of the
    jurisdictions by which they are expressed to be governed;

(h) that the Subject Agreements are in the proper legal form to be admissible in
    evidence and enforced in the courts of the jurisdictions named therein and
    in accordance with the laws of such jurisdictions;

(i) that there are no provisions of the laws or regulations of any jurisdiction
    other than Bermuda which would be contravened by the execution or delivery
    of the Subject Agreements or which would have any implication in relation to
    the opinion expressed herein and that, in so far as any obligation under, or
    action to be taken under, the Subject Agreements is required to be performed
    or taken in any jurisdiction outside Bermuda, the performance of such
    obligation or the taking of such action will constitute a valid and binding
    obligation of each of the parties thereto under the laws of that
    jurisdiction and will not be illegal by virtue of the laws of that
    jurisdiction;

(j) that the records which were the subject of the Company Search were complete
    and accurate at the time of such search and disclosed all information which
    is material for the purposes of this opinion and such information has not
    since the date of the Company Search been materially altered;

(k) that the records which were the subject of the Litigation Search were
    complete and accurate at the time of such search and disclosed all
    information which is material for the purposes of this opinion and such
    information has not since the date of the Litigation Search been materially
    altered;

(l) that the Resolutions are in full force and effect and have not been
    rescinded, either in whole or in part, and accurately record the resolutions
    adopted by all the Directors of the Company as unanimous written resolutions
    of the Board and that there is no matter affecting the authority of the
    Directors to enter into the Subject Agreements, not disclosed by the
    Constitutional Documents or the Resolutions, which would have any adverse
    implication in relation to the opinions expressed herein;

(m) that the form of Subject Agreements which we have examined for the purposes
    of this opinion do not or will not differ in any material respect from those
    agreements approved by the Board of Directors pursuant to the Resolutions,
    and that, when executed and delivered, the Subject Agreements will be in a
    form which does not differ in any material respect from the drafts which we
    have examined for the purposes of this opinion;

(n) that the parties to the Subject Agreements, other than the Company, have no
    express or constructive knowledge of any circumstance whereby any Director
    of the Company, when the Board of Directors of the Company adopted the
    Resolutions, failed to discharge his fiduciary duty owed to the Company and
    to act honestly and in good faith with a view to the best interests of the
    Company;

(o) that the Company has entered into its obligations under the Subject
    Agreements in good faith for the purpose of carrying on its business and
    that, at the time it did so, there were reasonable grounds for believing
    that the transactions contemplated by the Subject Agreements would benefit
    the Company; and

(p) that each transaction to be entered into pursuant to the Subject Agreements
    is entered into in good faith and for full value and will not have the
    effect of preferring one creditor over another.

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OPINION

Based upon and subject to the foregoing and subject to the reservations set out
below and to any matters not disclosed to us, we are of the opinion that:

(1) All necessary action required to be taken by the Company pursuant to Bermuda
    law has been taken by or on behalf of the Company and all the necessary
    authorisations and approvals of Governmental authorities in Bermuda have
    been duly obtained for the issue by the Company of the Securities.

(2) When duly issued and paid for pursuant to and in accordance with the terms
    of the Subject Agreements and the Resolutions the Shares will be validly
    issued, fully paid, non-assessable shares of the Company.

(3) When duly issued and paid for and when executed and delivered pursuant to
    and in accordance with the terms of the Subject Agreements and the
    Resolutions, the Rights will be validly issued, valid and binding
    obligations of the Company.

(4) The issue of the Shares and the issue of the Rights do not and will not
    violate, conflict with or constitute a default under (i) any requirement of
    any law or any regulation of Bermuda or (ii) the Constitutional Documents as
    that term is defined in paragraph 7 of the Schedule to this opinion.

RESERVATIONS

We have the following reservations:

(a) The term "enforceable" as used in this opinion means that there is a way of
    ensuring that each party performs an agreement or that there are remedies
    available for breach.

(b) We express no opinion as to the availability of equitable remedies such as
    specific performance or injunctive relief, or as to any matters which are
    within the discretion of the courts of Bermuda in respect of any obligations
    of the Company as set out in the Subject Agreements. Further, we express no
    opinion as to the validity or binding effect of any waiver of or obligation
    to waive either any provision of law (whether substantive or procedural) or
    any right or remedy.

(c) Enforcement of the obligations of the Company under the Subject Agreements
    may be limited or affected by applicable laws from time to time in effect
    relating to bankruptcy, insolvency or liquidation or any other laws or other
    legal procedures affecting generally the enforcement of creditors' rights.

(d) Enforcement of the obligations of the Company may be the subject of a
    statutory limitation of the time within which such proceedings may be
    brought.

(e) We express no opinion as to any law other than Bermuda law and none of the
    opinions expressed herein relates to compliance with or matters governed by
    the laws of any jurisdiction except Bermuda. This opinion is limited to
    Bermuda law as applied by the Courts of Bermuda at the date hereof.

(f)  Where an obligation is to be performed in a jurisdiction other than
     Bermuda, the courts of Bermuda may refuse to enforce it to the extent that
     such performance would be illegal under the laws of, or contrary to public
     policy of, such other jurisdiction.

(g)  We express no opinion as to the validity, binding effect or enforceability
     of any provision incorporated into any of the Subject Agreements by
     reference to a law other than that of Bermuda, or as to the availability in
     Bermuda of remedies which are available in other jurisdictions.

(h) Where a person is vested with a discretion or may determine a matter in his
    or its opinion, such discretion may have to be exercised reasonably or such
    an opinion may have to be based on reasonable grounds.

(i)  Any provision in the Subject Agreements that certain calculations or
     certificates will be conclusive and binding will not be effective if such
     calculations or certificates are fraudulent or erroneous on their face and
     will not necessarily prevent juridical enquiries into the merits of any
     claim by an aggrieved party.

(j)  Any reference in this opinion to shares being "non-assessable" shall mean,
     in relation to fully-paid shares of the Company and subject to any contrary
     provision in any agreement in writing between such
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     Company and the holder of shares, that: no shareholder shall be obliged to
     contribute further amounts to the capital of the Company, either in order
     to complete payment for their shares, to satisfy claims of creditors of the
     Company, or otherwise; and no shareholder shall be bound by an alteration
     of the Memorandum of Association or Bye-Laws of the Company after the date
     on which he became a shareholder, if and so far as the alteration requires
     him to take, or subscribe for additional shares, or in any way increases
     his liability to contribute to the share capital of, or otherwise to pay
     money to, the Company.

(k) In paragraph (1) above, the term "good standing" means that the Company has
    received a Certificate of Compliance from the Registrar of Companies.

(l)  Searches of the Register of Companies at the office of the Registrar of
     Companies and of the Supreme Court Causes Book at the Registry of the
     Supreme Court are not conclusive and it should be noted that the Register
     of Companies and the Supreme Court Causes Book do not reveal:

     (i)  whether an application to the Supreme Court for a winding up petition
          or for the appointment of a receiver or manager has been prepared but
          not yet been presented or has been presented but does not appear in
          the Causes Book at the date and time the Search is concluded;

     (ii)  whether any arbitration or administrative proceedings are pending or
           whether any proceedings are threatened, or whether any arbitrator has
           been appointed;

     (iii)  details of matters which have been lodged for filing or registration
            which as a matter of general practice of the Registrar of Companies
            would have or should have been disclosed on the public file but have
            not actually been registered or to the extent that they have been
            registered have not been disclosed or do not appear in the public
            records at the date and time the search is concluded;

     (iv)  details of matters which should have been lodged for registration but
           have not been lodged for registration at the date the search is
           concluded; or

     (v)  whether a receiver or manager has been appointed privately pursuant to
          the provisions of a debenture or other security, unless notice of the
          fact has been entered in the Register of Charges in accordance with
          the provisions of the Act.

Furthermore, in the absence of a statutorily defined system for the registration
of charges created by companies incorporated outside Bermuda ("overseas
companies") over their assets located in Bermuda, it is not possible to
determine definitively from searches of the Register of Charges maintained by
the Registrar of Companies in respect of such overseas companies what charges
have been registered over any of their assets located in Bermuda or whether any
one charge has priority over any other charge over such assets.

(m) In order to issue this opinion we have carried out the Company Search as
    referred to in the Schedule to this opinion and have not enquired as to
    whether there has been any change since the date of such search.

(n)  In order to issue this opinion we have carried out the Litigation Search as
     referred to in the Schedule to this opinion and have not enquired as to
     whether there has been any change since the date of such search.

DISCLOSURE

This opinion is addressed to you in connection with the registration of the
Shares and the Rights with the Securities and Exchange Commission and is not to
be made available to, or relied on by any other person or entity, or for any
other purpose, without our prior written consent. We consent to the filing of
this opinion as an exhibit to the Registration Statement of the Company.

We also consent to the reference to our Firm under the captions "Legal Matters"
in the Joint Proxy Statement/Prospectus which forms a part of the Registration
Statement.

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This opinion is addressed to you solely for your benefit and is neither to be
transmitted to any other person, nor relied upon by any other person or for any
other purpose nor quoted or referred to in any public document nor filed with
any governmental agency or person, without our prior written consent, except as
may be required by law or regulatory authority. Further, this opinion speaks as
of its date and is strictly limited to the matters stated herein and we assume
no obligation to review or update this opinion if applicable laws or the
existing facts or circumstances should change.

This opinion is governed by and is to be construed in accordance with Bermuda
law. It is given on the basis that it will not give rise to any legal
proceedings with respect thereto in any jurisdiction other than Bermuda.

Yours faithfully,

   /s/ APPLEBY SPURLING & KEMPE
- --------------------------------------
           Appleby Spurling & Kempe

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                                    SCHEDULE

      1. A copy of the Business Combination Agreement.

      2. A copy of the Joint Proxy Statement/Prospectus.

      3. A copy of the Registration Statement.

      4. The entries and filings shown in respect of the Company on the file of
         the Company maintained in the Register of Companies at office of the
         Registrar of Companies in Hamilton, Bermuda, as revealed by a search on
         21 July 2000 (the "Company Search").

      5. The entries and filings shown in respect of the Company in the Supreme
         Court Causes Book maintained at the Registry of the Supreme Court in
         Hamilton, Bermuda, as revealed by a search on 21 July 2000 in respect
         of the Company (the "Litigation Search").

      6. Certified copies of the minutes of the meetings of the board of
         directors of the Company held on 16 December 1999 and 15 March 2000
         (the "Resolutions").

      7. Originals of the Certificate of Incorporation, the Memorandum of
         Association, the Certificate of Incorporation on Change of Name and the
         revised Bye-laws (adopted 22 March 2000) for the Company (collectively
         referred to as the "Constitutional Documents").

      8. A Certificate of Compliance, dated 20 July 2000 issued by the Ministry
         of Finance in respect of the Company.

      9. The original "Foreign Exchange Letter", dated 14 December 1999, issued
         by the Bermuda Monetary Authority, Hamilton Bermuda in relation to the
         Company.

     10. The original "Tax Assurance Letter", dated 13 January 2000, issued by
         the Registrar of Companies for the Minister of Finance in relation to
         the Company.

     11. The original Register of Directors and Officers in respect of the
Company.

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