For me, the best Alevel books for chemistry were: -chemistry through diagrams: really helpful and useful chock full of information
Also calculations for Alevel chemistry is another beautiful book with explanations examples and loads of practice questions for all the calculations you'd ever need in chemistry and even the first semester of year one uni
For physics I also used to swear by the physics through diagrams book
I also had a book called one thousand solved problems on physics, I never used it much, but it was one huge book at least 5 inches thick. Oh and if your school or college is subscribed to the CP factsheets these are also indispensable sources of information that will make your life easier. If your school is not subscribed, then googling them you will find most of them, but sadly not all the collection.
Did a foundation year in chemistry this year, it covered the very basics right through to the A-level topics. But unlike A-level text books it is designed for learning chemistry with little or no teaching help. So it is perfect for self-teaching.
Palgrave also do a physics one, I also own that but never used it as I decided not to study physics this year. But I'm sure it is also pretty good.