Hi, me again. Chris, have you tried the British Racing Drivers Club? They were started in 1928 by some of the 'Bentley Boys' from the LeMans days and now have a full time archivist ...
http://www.brdc.co.uk/Archive
... who may be able to help. Just to give hope, I saw a display there (Brooklands) years ago which included photos of one of the pre-war drivers in racing kit and then in his wartime RAF uniform. Sadly, I don't remember his name.
Regards,
Bruce