You'd probably have been better posting this off in the jobs/careers section.
I must admit, after a fairly quick Google search, you seem to be correct about there not being much info out there on the trade training. It looks like it's at RAF Cosford & lasts for 6 months but I don't know how up to date that info is.
I'm in the RAF as an FOA & until about 2 months ago I'd never even met an RAF photographer so it must be a small trade.
The best way to discover what they do is take visit to a photography section on an RAF base. This will enlighten you & ensure you look great in your interview when they ask you what research you've done.
The only thing I've seen them do is passport/ID pics so I'm not a good person to ask.