What books should I buy for A Level Chemistry, Physics, Further Maths and Maths?

Anyone know of edexcel Maths books (c1-4, s1, m1) with hard and challenging questions whether they are exam style or not so much but useful questions. the ones in books that are most commonly used like this which is the most popular: https://www.biochemtuition.com/wp-content/uploads/2015/07/131310607-Edexcel-Maths-C1-2.pdf just don't cut it they are too straight forward and don't seem like enough.

Anyone know of edexcel Maths books (c1-4, s1, m1) with hard and challenging questions whether they are exam style or not so much but useful questions. the ones in books that are most commonly used like this which is the most popular: https://www.biochemtuition.com/wp-content/uploads/2015/07/131310607-Edexcel-Maths-C1-2.pdf just don't cut it they are too straight forward and don't seem like enough.

The ones mentioned above are said to be quite challenging

maybe its because i started with c1 which is easier than the others and very similar to GCSEs so it could get harder.