Hi oab, I'm not sure if you tried Mathnasium after all, but I have just trialed it for a month with my 7-year-old son and have been more than impressed. Feel free to read my review:
viewtopic.php?f=115&t=107711
Clearly Year 2 maths is very different to GCSE, but the concept is the same - to make maths understandable, less scary and actually fun. I would encourage you to speak to John Preston, the Centre Director on Northcote Road and take it from there.