Kayce: The venue is a large ish indoor sports hall
http://www.youtube.com/watch?v=25ALnMPEsCE
I run 10.5T in my B44 no problem, some guys are running 6.5 but that thats just silly indoors. as a comparison my B44 rear diff feels a lot looser than the B4 so i think that may be where the problem lies. It was 6 months ago when me and my B4 fell out and I feel ive got much better since then.
Dexter: I'll have a look at the whole gearbox, strip and rebuild as per manual then start over
Bradders setup for worksop should be a good starting point