[Darren69]

Ok, just thought I would post up because the part from post #2 turned up yesterday afternoon. I checked the resistance of it off the bike and if was low to virtually nothing so I conclude from that the switch is closed in static position.

I removed the one I that was fitted and the differences were obvious but not so much. The one I removed was stainless and much heavier than the cheapo one. No surprise there. The copper washer supplied with the cheapo one was a very thin brakeline banjo bolt type and the one from the bike had a large aly flat washer that fitted nicely into the flat machined into the cover, so I re-used that. If it leaks a bit I will replace it but it will do for now. The only other differnce was the threaded part was 2-3 mm shorter than the one removed and I don't know if that would have any impact.

Upshot is that the even with the replacement unit the light still stays on just the same, so it looks like I'll be chasing an electrical issue or I really do have no oil pressure, which I don't think but who knows2