Sounds like Cheethams or something like that if it's a music schools which limits the number of GCSEs.
I just want to write something which I saw recently, I think on Morgan Stanley Dean Witter's recruitment webpage, which went along the lines of, 'If you meet the required grades, you are academically capable, but what we are interested in in the selection process is examples of how you have excelled outside of the exam hall.' This is particularly true for most jobs for intelligent people nowadays. Varied extra-curricular life is a must, and I would caution you from dropping something which you obviously excel at.
And don't forget it as taildragger says: far better have somebody pay a bit of it than you pay for all your training.
You cannot fly 777s as a new trainee with a new licence in BA until you have the required hours on licence and in company. Two years is a tad optimistic. Try five at an absolute minimum.