You are right, I have seen CCF in quite a few independents but the school visit itself used to take up so much of time that didn't get much time to talk them. High standard of discipline is really good, if my boys can handle that then that will great. My boys are interested in music, already doing piano and guitar so they might like that part of ATC as well.
I saw in the ATC website about flying and gliding which sounds very interesting, they are very passionate about plane models so out of that passion if they love ATC then that will be good. Specially when they can join from Year 8.
My main concern will be whether they will be physically fit enough to carry on with ATC as currently they are not very athletic, they are not with too many physically challenging sports.
Thanks a lot for your useful tips,