GIJoe - did you get a sense of humour bypass at some point in the past.
As I said, it IS theoretically possible to join the RAF from the Army - but in over a decade in the service I NEVER met anyone who admitted to having been in the Army first.
You may know people who were - I do not.
SMILE for God's sake - it's called BANTER!
EDIT: Just remembered one - an ex AAC MT driver who became an RAF Policeman. I stand corrected.