Don't do A-level maths unless you really enjoy it, and almost a natural at it. Everyone I know who took A-maths because thats what pilot guides recommended, got totally fed up and either did really poorly or dropped the subject after the first year. Its a big jump up from GCSE maths higher papers.
Provided you work hard on your GCSE maths course, you will have all the basic knowledge you need for ATPL's. The big problem with the ATPL's is the volume of work in the time available. You can never be fully prepared for it!
Before deciding on A-level subjects, think what degree courses you might be interested in should the flying not 'take off' for whatever reason. research fully into this because it may influence your A-level subject selection.
Also, sixth form culture seems to get students better grades than the regional colleges.
[ 20 October 2001: Message edited by: kingfisher03 ]