Thanks Keith, but yes, the oil is coming from the bolt. Took the cover off and the inside was dry. SJ repalced the output shaft seal for me last year and it hasn't failed since. He said Ducati were producing new ones cos they failed so much.
With the engine running and the clutch cover bolt out, the oil globs out quite freely and down the cases.
Thanks for the tip Jon on the PTFE tape...hadn't thought of that......now how can I get hold of some of that from Wolseley....
:P