To start:
http://www.nationalarchives.gov.uk/
Follow the Military History >> more military history links; there's a ton of stuff about everything on this National Archives site, though. Keep you busy for days!
To continue, subject an officer or OR:
http://www.veterans-uk.info/service_...e_records.html
Service Records. He's on his own here, because I haven't read through all this, but this gives him the conditions, restrictions and links for contact information etc.
Tell him good luck and have fun! And I, at least, would like to see what comes out of this, if he doesn't mind...
