If the year is not known use Halsbury's Laws, starting with the Consolidated Index unless the subject is evident from the spine of one of the main volumes. You may need to try a variety of keywords. Halsbury's Laws, which is a guide to both legislation and case law, runs to 52 volumes, including 2 concerned with European Union law.
Supplements appear when there is a major change to the law.
Annual Abridgments record such changes as have not yet been made to the main volumes. The Current Service volumes contain monthly updates on recent changes, the Noter-up volumes briefly annotate the main volumes and the abridgments. The Consolidated Table of Statutes, in 2 volumes, lists statutes alphabetically, with reference to their citation in the main volumes. The second volume also contains a Table of Statutory Instruments. Current Law Monthly Digest contains a monthly summary of changes to the law, including Scots, Irish and European Union law, arranged by subject, plus a Table of statutory Instruments and a Statute Citator.