Hi Nick, the cup with the grub screw in was as far forward (toward the drive shaft) as it could be as any further meant the
grub screw was sitting on the round part of the slipper shaft instead of sitting in the cut out section.
Now I have taken the diff out and reinstalled it the problem has gone which I dont fully understand as it appeared to be flush the first time but there must have been a slight kick up somewhere as its no longer a problem.
Thanks for all the help and advice guys, it's much appreciated!
