New Spec you can still use past papers for. I haven't found being on a new spec any disadvantage other than having to combine a few modules for chemistry. They still follow on, eg for OCR Chem the first question was still (as it is in the majority of the past papers) define relative isotopic mass and on isotopes for module 1... question structure hasn't really changed at all.
I couldn't have gottan A's using just CGP revision guides.. I used the syllabus as a referance point, the text book that came with the course, lesson notes and then looked up anything in other revision books I had or on the net that I didn't fully understand after everything else. Syllabus specific books are the best as although the majority of all the courses are similar, they are not exactly the same and so generalised books will miss out some stuff you need to know or go into too much detail into something you don't.