| Thanks for your input guys....
I'm pretty sure it's behind the bearing carrier - I have pulled the belt covers off, cable tied everything out of the way and after cleaning up all the oil, run the bike without the covers. It has also had the cam seal itself replaced before and is still leaking.
Understand what you say about the gasket on the rocker/oilway cover, but again, it doesn't look like that's the culprit.
Basically, that only leaves the O ring behind the bearing carrier....
I will have to get onto DOC and see if I can hire the locking tool for pulley removal then!
thanks
Bon | 
Threaded Mode