Pre war trials are covered in The Autocar, The Motor and the Light Car. At this time trials received the kind of interest modern day rallies enjoy and reports are very detailed, and include previews the week before. These magazines are available at various libraries, including the National Library of Wales at Aberystwyth, Coventry Central Library, the Bealieu Museum and the Rover Heritage Centre at Gaydon in Warwickshire. Bealieu also houses a huge photographic archive. Autocar and Motor continued to cover the events until the late 1950s.
The ‘bible’ for classic triallists is C.A.N. May’s famous book Wheelspin, a first hand account by a trials’ enthusiast covering the years 1933 – 1939. It was published in 1945 by Foulis and reprinted by them in 1971. In 1948 C.A.N. wrote a sequel ‘More Wheelspin’, covering the immediate post-war events and is written in the same interesting and amusing way. This was also published by Foulis.
For those who like detail Donald Cowbourne’s excellent books ‘British Trial Drivers, their Cars and Awards 1929-1939’ and ‘British Trial Driver, their cars and awards 1919-1928’ can be recommended. No stories here but a wealth of information and lots of good photographs. Published in 1998 and 2001 respectively they are available @ £36 each from Smith Settle, Freepost LS5407, Otley, West Yorkshire, LS21 1YY.
A history of the MCC by Peter Garnier, published in 1989, gives a lot of history of the three long distance events, the Exeter, the Lands End and the Edinburgh.
These books may be available through second hand bookshops or ask at your local library, they should be able to borrow any of the books above from the British Library.