I'm pretty sure when I revised for GCSE maths there were some youtube teachers covering the whole of GCSE AQA maths in around 4 hrs. You might not understand it though if you haven't already been taught it as it's going over everything rather than teaching from scratch. But you could check it out, just put whole of GCSE maths syllabus or something similar into Youtube.
I also recommend the CGP books, they lay everything out really clearly. Much easier to revise from than my notes!