Motorcycle and Scooter appreciation

Check the level then ;)

Is there a missing o ring or something?

Is it a bonnie?

plenty of oil
It's a Bonnie (well a Thruxton, which has sort-of-rearsets, but that bit's the same)

The leaky bit is the gearchange shaft itself, which is a rubber oil seal rather than a paper thing.

I'll give them a call. I reckon they've fucked the seal up when they installed it.