Hmm, secondary is well within tolerance, but primary seems on the limit, but difficult to measure properly as it is well inside the engine and I have thick fingers.
I think I may have to go for replacing both... as the engine is apart. Then at least I know it is all new and OK.
I guess the hunt is on for a new set of chains! I saw a thread on this site somewhere...
Gonna be pricey no doubt and then I'll have to find someone willing to put them in as splitting the crankcase is beyond my spannering ability...
Paul