FIXED

I now have a new favorite tool. The torque wrench.

I seems the problem was that the initial seating of the bearings was not tight enough.
I pulled it all apart, checked for any damage I might have caused, greased it all up again and torqued the nuts up to 30Nm. Backed the nuts off half a turn, torqued them back up to about 5Nm until there was no play in the rotors, locked the nuts off and tapped the caps back on.
On with the wheels and time for a smoke. Fingers crossed.
Took it for a run and, lo and behold.
FIXED.

Thanks every one for your help, this is a great site, I'm learning a lot from you guys and saving money at the same time. Thanks again.