Does anyone know how to get rid of surge?
I'm not 100% sure that it is surge (hesitation between about 3 an 4k revs in
4th,5th and 6th), but if it is???
Would a different turbo help?

 

Doubt you'd be getting surge with a standard turbo.

I had massive surge problem with a hybrid turbo 'not of my spec'. It's not just hesitation. You get waves of acceleration.

My Grandad used to pump his accelerator in time to the music he was listening to. :-) It's a bit like that.