Pulled the alt-cover off yesterday :
Looks new!
I also pulled the plugs (used, but still very usable),
the lower plugs were more oily - but I'd expect that (they're always manky).
I sprayed a small amount of light oil (3-in-1) into each combustion chamber, just to loosen off the rings (well - that was the idea). Left the engine for a bit, then rotated it using the alt-belt nut (a 16mm oddly, it's the only place I've ever seen a 16mm nut) and the engine turned over smoothly and quietly - all good!
I have a feeling that this bike had a full service just before being put away by the previous owner. The engine oil is a) slightly over-full, and b) bright red. It's obviously virtually new.
Which is more than I can say for the battery. I've had it on charge for a weeks or two now - trying to bring it back, and I put it on the bike yesterday to see if it would turn the bike over.....
Click-Click-Click-Click-Click-Click-Click-Click-Click-Click-Click
nope - no go. And it got noticeably weaker on the 2nd and 3rd attempts.
So - it may well be new battery time.
I've also replaced the broken fuel-line-connector but I've not yet replaced the tank and tried the bike with fresh fuel. That's the next step. I've got a jump-starter which I know has plenty of juice for this (used it on my other bike a few times), to get the bike started.
Still weighing up whether to go full-on and do all the "upgrades" (strip the ABS, replace the calipers and discs, etc etc).
I'll do a valve service once I get it running - but to road test it I'll need to get it MOT worthy and then taxed and insured.