It turned out to be the side stand switch.
Not sure how it managed the 10 second delay before cutting out, when I tried to ride it last week.
Moved the side stand around a bit and got it so it would cut the motor instantly with the stand down.
Took it off and, being a 2001 model, it was one of the switches with the plastic pin, so did well to last this long!
Couldn't seem to find an easy way to follow the cable route and find the plug to mod the wires, so carefully filed what was left of the pin down, so it would no catch in the hole and work the rotary switch. Turned the switch to position when stand is up, and jammed it up so wouldn't easily move, then greased the face well so stand would not move it round, re-assembled and fine. probably not the best botch up, but no replacement in my spares stock, so need to order a new switch and just had to get out in that sunny weather.
Also modded the stop on the eBay side stand, (i.e ground it down a bit), so it now folds away a bit further, I have had no other problems with it,
so reckon it is a good replacement.