Oh Oh!

Went to unstrap the bike from the car deck of the ferry this morning and horrors! There's a spot of oil on the floor under my gearbox.
Maybe it was there before I parked the bike?
A quick check reveals a little drip from the engine :-( it's not pouring out but it's certainly not right. We did push the bikes quite hard yesterday in terms of running hours and top speeds (long runs at an impressive 50mph!) so maybe this is to be expected??? But how much oil have I lost?

Now I wish I'd checked that gearbox oil before leaving Italy - fingers crossed (again) for a hassle free ride to my mum and dads today