No need for A-Level Maths - I scraped a C in Maths at GCSE level & went onto study Geography Biology & Ancient History at A-Level. If you do a good ATPL course they will teach you or bring you up to speed on what you need to know. Your sheer determination & motivation play a far larger part in gaining your ATPL than pure academic knowledge. My choice of A- Levels has made no impact on my flying career. Choose something you find interesting & enjoy would be my advice.