What is important is that you have sufficient grey matter to cope with the 14 EASA exams and your brain is wired correctly for flying.
So as a minimum 5 GCSE including maths, physics, and english.
2 A levels indicate sufficient mental capacity / IQ / call it what you like
That is not to say that you will not succeed without 2 As.
The hardest it gets is SIN COS TAN plus basic physics BOYLE / CHARLES LAW
You need a basic education in this aviation game. The course can be thought of as high volume, low grade material. First time passes in ALL subjects.
The acid test is getting a really good mark (90%+) in the NAVIGATION paper.
Fewest facts to learn, but all about UNDERSTANDING.