I haven't actually finished working through it, but moved on to the revised, updated edition "GCSE Higher Mathematics."
This is a decent book, covering topics from revision of basic maths to more advanced stuff like trigonometry and statistics. Given that this edition was published in 1992, it's a bit dated - especially when it comes to the financial section and examples regarding wages and VAT rates. Somewhat surprisingly, there are sections with exercises/investigations you are encouraged to do on a computer, but again, the programs referred to are now presumably obsolete.
There are generally plenty of exercises for each topic, although the main issue I had with this book was that occasionally, it would introduce a sub-topic with an example given, then expect you to solve questions without having actually explained the example sufficiently that I could understand what steps had been taken in the example and why. The updated edition already looks as if it has corrected at least some of these issues - particularly in Chapter 2.
Even though I haven't done a huge amount of it, it has already helped me to become more confident with my maths skills, and I look forward to continuing that progress with the revised edition.