Dowloaded a copy and have taken a good look.
I'd say it was easily comparable to (and depth-wise exceeds in several instances), A-level physics in the core topics. However, some A-level options such as astrophysics are missing though.
If you are coping with this book, then you should have no problems with an A-level syllabus but you may need some additional subject matter to complete certain A-level topics not covered by the FoP book.