1. I have checked I have the correct clutch plate by testing it of the gearbox spline.
2. I have centred clutchplate - albeit with a home made tool - but I think it is good.
3. I also checked the spigot bush was a good fit before fitting it the the crank.
Any tips please? Or would anyone like to come and help even....
One slightly odd thing I noticed, although it won't stop the gearbox fitting, is that the roller bearing spigot bush doesn't fit quite flush with the end of the crank - it protrudes about 3mm. See picture. i have tapped it as hard as I dare and I am pretty sure it has gone in as far as the little locating shoulder in the crank.
engine_crankshaft_bush by Robin Martin, on Flickr