ZX5 Drive Problem

[Dazzieboy]

So I did my first regional at the weekend and in morning practice the car was flying and I was really happy with it. Then as the grip reduced during the day the car got worse and worse. The problem was that it appeared to be sending all of the power to the rear wheels out of corners meaning I was just spinning out and generally doughnutting. I'd never experienced this with the car before so didn't really know what to do. I've managed to strip the car down tonight hoping to find something obvious. I've rebuilt the slipper and both diffs then put on some really low grip tyres and went on the back garden to test it trying to simulate low grip conditions. Well the car is still the same when I put my foot in front of it and blip the throttle all 4 wheels spin so I know there is power going to the front but when powering out of a bend all the power seems to be going to the rear. This is an original kit ZX5 BTW and I have a white slipper pad at the front and red at the rear.

Please help!