Chris,
Some good advice above from the likes of Seak1ng, Rude C'man and Talking Radalt; they obviously know what they are talking about. As for SARBoy Losers comment, well, read his other posts and you will see he obviously has a problem with the RAF.
Current retention and recruiting difficulties mean that the RAF is having to take a much more flexible approach at the moment.
Get to your nearest Careers Information Office (or whatever they are called these days) and negotiate.
Good luck,
Fay