right, Monday after wok update:
removed the tensioner tonight....seems you were right Chris, the ring was "squeezed" (to put it lightly!) funnily enough, it was the outer ring of the casing, not the inner ring?! It screwed in so easily as well, I feel like a bit of a dork....
Heres the tensioner:
http://www.ballardshaw.co.uk/storage/tensioner.JPG
whats left of ring - excuse poor quality:
http://www.ballardshaw.co.uk/storage/squashed.JPG
I will rebuild with a new ring tomorrow, and see what happens, I checked the tensioner hole in the block and it appears I didnt cause any other damage so it should be ok.
One last thing, the chain skipped a notch during all this. The pic below is the cams when the O/T mark is aligned and the rotor is pointing exactly at the notch in the case. Do you think the left hand cam needs to come down a notch, or do you think the right hand cam needs to come up a notch?
http://www.ballardshaw.co.uk/storage/notright.JPG
Phew, nearly finished......
Thanks. Steve.