update:
finally collected the rocket today and what a difference!
Martyn overlaid the before and after dyno graphs on the pc to look at. Spool up is approx 500rpm sooner and the difference at 4000rpm is amazing...........60bhp & 90lb/ft.
Did a couple of runs with Martyn before coming home and put the foot down in 5th, you can feel the back end squat, rear diff tighten and there is a pressure pushing the chest backwards...............like nothing I have felt before.
Many many thanks to Martyn & Alan again for preparing my car again.