Lizz, I don't think there is much by way of Maths in the PPL syllabus. Speed/ distance and time is about as tough as it gets! There's also a bit of unit conversion but it can all be done fairly simply on the whiz-wheel (CRP-1 flight computer). Knowing a bit about trigonometry might be useful, but is definitely not essential. If you got Maths and science GCSEs or similar you won't have any trouble.