Congrats on the car Ian
As said before some transmission noise when low speed manoeuvring due to lack of cush in drive train. However like Nick I wouldn't say it's like a bag of spanners.
Diff maybe, though if you're reversing straight LSD isn't working.
Problem in gearbox not impossible though I think, if not mistaken, it would be the first time one was reported on here. The Getrag box is a very strong unit so you would be unlucky if problem there.
Perhaps worthwhile jacking back end up and turning wheels to see if any strange noises?
Cheers
