Think I have worked this one out now, and feel a bit of a plank. Despite virtually any setup changes I made, the problem never really went away. I am using JC wheels, and tried taking the inside and outside rows off the fronts. I had another pair of fronts on Associated wheels which only had the middle 4 rows left, from ages ago. I tried these in the second round, rather than trim the originals down more. Imagine my surprise when the car went from a difficult hooky snappy monster, to a slightly understeery very stable car! Apart from the slightly wider wheels, the only difference is the Associated wheels have got a decent insert, where the originals feel like they have hardly anything in them! The tyre wall must have been collapsing and making it very unpredictable. Just to try, I trimmed them down to the same as the other wheels, and the monster was back, but not quite as bad. The moral is, dont use crappy old inserts you find lying around
