Reddit mentions of Edexcel Mod Maths Further Pure 1

The Physics AS/A Levels are a funny lot of modules; I believe they're designed to be doable without any A Level-equivalent Maths knowledge, so they're riddled with weird explanations that really try to avoid maths - which often just makes everything harder in the long run. (I did AQA Physics A, but all were pretty similar as far as I gathered.)

With that in mind, if you're looking to study Physics further on, I'd recommend supplementing your mathematics. If you're doing Further Maths, you probably needn't bother, as the first year of any university course will bore you to death repeating everything you learnt about calculus etc.; if you're doing single Maths, I'd recommend getting confident with C1-4, and maybe purchasing the Edexcel (Keith Pledger) FP1/FP2 books to get slightly ahead before uni. They're great books, so might be useful to have for Y1 of uni and reference thereafter regardless. I was quite put off by the attitude towards Y1 maths of the Further Maths people (about half the cohort), who kept moaning about having done it all already, so found focusing in lectures a tad harder; I wish I'd bothered to read just a little ahead.

The second thing I'd recommend would be reading fairly broadly in physics to understand what aspect in particular you enjoy the most. In my experience, the students who have even a rough idea of what they want to do in the future perform better, as they have motivation behind certain modules and know how to prioritise for a particular goal, e.g. summer placement at a company which will look for good laboratory work, or even as far as field of research.

To that end (and beginning to answer the post!), books that aren't overly pop-science, like Feynman's Six Easy Pieces/Six Not-so-Easy Pieces are good (being a selection of lectures from The Feynman Lectures). Marcus Chown does a similarly good job of not dumbing things down too much in Quantum Theory Cannot Hurt You and We Need to Talk About Kelvin, and he talks about a good variety of physical phenomena, which you can look up online if they interest you. I could recommend more, but it really depends how you want to expand your physics knowledge!

E - darn, just read you're not in the UK. Oops. Mostly still applies.