Lots of freeing oil, a big hammer, various pullers and the engine is coming apart.
The gudgeon pin is out, the little end bearing seems serviceable, maybe things aren't as bad as I thought.
The bottom end is now sat soaking, we'll see what happens tomorrow.
On the plus side, I removed a panel from the petrol tank and can cofirm that it really is a black bike,
so black and chrome/silver it is then...