Looks like the temperature sender has had it.
One of these it think, http://www.scooter-works.co.uk/parts...t_sub_type=435
Don't know if any resets are needed on any electronics or such though, too new for me. I would expect it to be a straight swap.
WITH THE ENGINE COLD, unbolt the broken unit, have the replacement ready as a bit of coolant will come out, then screw the new one in with a new sealing washer. Connect the electrical connection. Enjoy.
Should take longer to wash your hands unless there is lots of bodywork In the way.
thank you bankofdad!