Managed to get the crank lined up after some persuasion with the hammer. Didn't go mad at it but just using its own weight the hammer was able to get the crank seated right and equal distances on each side. Many smiles and sighs of relief after that one.
Have moved onto getting the last of the frame pieces off before sending away for painting. The suspension linkage had a similar problem to the swingarm in that the internals appeared to have just welded together with corrosion. After a bit of headscratching ( and breaking a chisel trying to beat the bolt out!) I grabbed the angle grinder and convinced the linkage to change its attitude. Great success and a pretty neat job if I do say so, problem is now I'm down a linkage and need to source a replacement. Keeping an eye on eBay but nothing looks great atm. Anyone happen to have a spare?
Only thing left to get is the lower race bearing in the headstock then time for shiny new frame