BA base allocations

[flying Dr]

I was hoping someone could answer a question-I was initially led to believe that all BA cadets were allocated a posting at either heathrow, gatwick, birmingham or manchester. Now ive heard talk of cadets being streamed onto the rj and atp, which surely cant al fly from the above-do BA only send their cadets to the mailine fleet or do they "lend" them ot to the franchise and subsidiary airlines?

And question number 2,
How many months of the year do you have to be living outside the uk to claim your tax back?