Thanks again all.

I swapped over the floats and needle valves for 'normal' ones, and symptoms were the same, so I decided to look at the damper springs as a bit of a last hope. The ones in there were huge, and very strong, so I put in some shorter, weaker ones. That has made a huge difference, much more than I could have imagined. I don't as yet have the correct red springs (4.5 oz)in there as yet, I will order them. Although I have been able to dial the jet down because of the above, the jet is still quite high up, but if that's where it wants to be, c'est la vie. I really am amazed at the difference those other springs made.