Self learn calculus for uk a-levels?

I am currently about to begin self studying for UK maths a-levels, however I am also wanting to gain a solid understanding of calculus. I know that calculus is covered in a-levels, but, the books for a-levels seem to be not as dense or as good as the US books I believe.

My question is this. Would a calculus book better explain calculus than general maths a-level books? And would it be a wise decision to study primarily off a calculus book and fill in all extra gaps required for a-leave in the a-level books?

Any advice would be very helpful. Thanks.

You said you are about to start studying A-Level Maths, so I think it might be slightly early to think about undergraduate calculus books, such as Spivak. I would recommend 'Pure Mathematics 11' and 'Pure Mathematics 22' by Bostock and Chandler. Despite being written a long time ago, these are the best A-Level textbooks I have ever seen; newer books tend to omit a lot of important proofs.

You are also right to point out that high school calculus in the US (such as AP Calc. BC) tends to cover more calculus than is taught in A-Level Maths and Further Maths. Elementary calculus/real analysis topics not covered in A-Level Maths and Further Maths include continuity, techniques for evaluating limits, and convergence and divergence of sequences and series. In the UK, such topics are typically taught in the first year of an undergraduate maths degree.