gconnatyuk-
Mate, some advice don't waste your time joining the RAF as an FOA (ATC)/ATCA!
If you have the aptitude for controlling, then get your tail over to Eurocontrol or NATS. The money is better and prospects are much brighter and you're not going to get dicked around for three years making the tea and doing pointless 'Duty Driver' duties in crap parts of the country or worse in Iraq or the Falklands.
You can make use of those three years as a civil controller to good advantage to get yourself firmly established on their career ladder.
PS. I am an ex Mil controller, so feel free to PM me if you do decide to go the Mil route for more advice.