I got B,C,E at A Level and then graduated from a good uni with a first in politics.
I think you should be more concerned about your chances with the RAF than in civil aviation. I was offered a Sixth Form scholarship as well as a Flying Scholarship despite the fact that I've got really bad eyesight. This illustrates how you shouldn't be misled into thinking they really want you simply because they gave you an award.
In this game, what really matters is whether you have the aptitude, and this will be tested rigorously at interview. You will almost absolutely have to sponsor yourself through training. It's a long hard slog but the question to ask is: how much do you want this lifestyle?
What are you doing at Westminster? My partner is their admissions officer so she may be able to give you some constructive advice on the course you're doing.