Hiya Sauceball,
I got asked my preference for Aero/Area when speaking to HR when they called me to say I'd passed Stage 3. At that time I asked what course I was likely to end up on (I have a very complicated work situation at the moment which required some hefty amounts of notice)!
Departure Lounge stuff was sent to me after I'd passed my medical and they'd more or less confirmed that I'd be on course 220.
Personally I'd call them and ask - they should at least be able to give you an idea of course availability.