I completed my a-levels last year in Maths, Physics, Art & General Studies with an AS in Design & Technology.
I took Maths and Physics because I felt it would help me a great deal in the future with respect to flying and I did find the courses interesting. I chose the others because I really enjoyed those subjects!!
Don't worry to much about what other subjects you do! Take jollypilots advice and pick whatever you are good at and what you enjoy!!!!
Good luck!