I did do A-levels. Waste of time really. Got a U in Math and Physics. I spent too much time reading FCOMs for 737s and A320s as opposed to my school books.
How well you do in A-levels has absolutely zero relevance to how well you do in ATPL theory.
In todays industry I think they are pretty much essential for entry in commercial aviation training and thereafter to achieve your first job as a cadet pilot.
In January, I went from my flight school to Boeing job at a European airline in 6 days, no a-levels, no contacts, no P2F, no cadet scheme and at a modular school with no airline links.
Partly luck, partly because I did everything in my power to make sure I got that job. But yes, A-levels will help.
Sadly, airlines like to use crap filters like a-levels. Totally unfair IMO, you can't categorise people who went to earn money to be a pilot 2 years earlier. But it's a filter you need to bypass or avoid.
If you think you'll do well, do them. If not, why waste time?