"However, I'm told I can choose to have 4 GCSE A*'s or one whole A level (I assume A*), which would be more beneficial?"
I doubt it would make a huge difference, which one you chose.
When you say your CO do you mean to do with CCF? I am also applying for pilot. Has your afco mentioned whether you are a required to to go to oasc before the scholarship, because i have heard that some applicants last year didnt have to undergo a medical for example...?