As Bamboo says, Sue, plus it might be worth posting on the .Com Books Board, otherwise.:_|
There follows a list of possible other sources of information, and ways of tracking copyright holders:
Write to the principal publishers of any particular author. Some publishers will give information to accredited researchers about recipients of royalties; others will forward letters of enquiry.
Write to the archivists responsible for major collections of an author's papers.
Contact authors' societies, which may be prepared to share information or to forward letters. The principal bodies here are the Society of Authors (84 Drayton Gardens, London SW10 9SB); the Authors' Licensing and Collecting Society (14-18 Holborn, London EC1N 2LE); and the Writers' Guild of Great Britain (430 Edgware Road, London W2 1EH0). For Ireland, it may be worth contacting the Irish Copyright Licensing Agency (The Irish Writers' Centre, 19 Parnell Square, Dublin 1), and for France, the Institut Mémoires de l'édition contemporaine (9 rue Bleue, 75009 Paris).
Contact the Book Trust (Book House, 45 East Hill, London SW18 2QZ), which keeps extensive files of author information, including some copyright information.
For manuscripts and primary sources, ask the owner of the documents for information about the copyright holder.
Write to biographers or other scholars who have worked on your chosen author.
Contact British literary agents who may have had dealings with your author.
Check the acknowledgements and notes pages of published works wholly about, or touching on, your author. Well-edited editions of correspondence often give information about a wide range of authors and public figures.
Check genealogical and legal sources. For authors likely to have died in England or Wales, the wills which are publicly available at the Probate Office in London are a rich (although time-consuming) source. For Scottish authors, it may be worth checking for information through the Scottish Record Office in Edinburgh.
Try author searches on the World Wide Web.
Send a letter to the author's last known address.
Check authors' directories and works such as the Gale Research publication Contemporary Authors.
For general copyright information, seek guidance from the Copyright Directorate at the Patent Office (25 Southampton Buildings, London WC2A 1AY).
When all else has failed, publish a notice in appropriate newspapers or journals. The Times Literary Supplement is recommended for enquiries about literary authors, whilst a notice in The Times is a recognised last resort when one wishes to demonstrate that all possible avenues have been explored.
Life is fighting
