I finally got around to looking at the clutch/starter interlock switch. The one on the clutch lever that stops you starting the bike unless the clutch is pulled in. The one I never knew was a thing for the first 50,000km until it started to work one day.
The switch itself is a really nasty looking/feeling piece of plastic crap, open to the elements. Nevertheless, once cleaned with contact cleaner it seems to work as intended. Plugged back in though, the bike once again starts with clutch in or out. Won't go with the switch unplugged though.
That's why I'm a mechanic, not an electrician