CLUNK,CLUNK,CLUNK,CLUNK

[unfazed]

Well as I said I put old sprocket on last night and,,,,, no Clunk today  . But the old sprocket has signs of hooking on it too.
Was a bit worried as it started to clunk quickly. But as I said was thinking of changing chain and sprockets. Going to be costly month as need new rear tyre, front brake is close to edge, and now chain and sprockets. Wee bit of overtime needed.
Thanks for pointing straight to sprocket.  . Help well appreciated.
Oh, and tried pulling chain at rear sprocket. And it does pull out :o , probably about 3mm without much effort.
Well time for coffee and thanks again.

It is best to set the chain to the tightest position half way along the swinging arm, this way you are pulling the most worn section of the chain from the sprocket.
In any case a new set of sprockets and chain are needed.