Guys
There is an AQC thread which covers all of your questions. This thread is really to discuss the hold pool situation.
http://www.pprune.org/forums/showthread.php?t=94832
Perhaps the mods can move your posts.
But to answer your questions anyway
Mooneyboy
It seems they just split the group, some do it on the Airbus and others on the 737NG, there’s no telling which one you'll be on.
aviator1977
People do fail. It seems that 90% of people pass. I believe you get £2000 if you pass the AQC, pass the type rating and complete the line training. Why would they give you money back if you fail?
I guess the question of whether you risk the £6.5k depends how much you want to be an airline pilot. If you have plenty of job offers coming in then don't risk it.
The best advice I can give in way of preparation for the AQC is to make certain that your Instrument Flying Skills are 100% up to speed. If you have any doubts get some sim time on an FNPT2 (you don't need to practice in an expensive jet sim).
Anyway, take a look at the other thread.
SW