Do the subjects you are good at...
It is not that significant...
The RAF and BA do not specify A levels by subject
Incidentally do study subjects that complement one another e.g.
English History Economics - A
or
Physics Chemistry Biology Mathematics - A
not
Needlework and Physics
and if you do a degree get one that gives you a fallback in case you are deemed medically unfit or the job market is
cr@p
e.g. Optics, Town Planning etc
not
B.A.(Hons) Silly Studies
Hope that helps...
English History Economics A Level