Thatís helpful most of which is checkbox on the bike. Testing the water temperature sensor to confirm resistances, Is it possible for the water temperature sensor to be out then and yet still signal the ECU to bring the temperature warning light on plus by now the coolant is starting to boil up and the fact that the fan isnít running have anything to do with the water temperature sensor ?
Apart from the ground wire to the relay all of the other three wires check out with the feed to the switch live the feeds of the relay coil live continuity to the fan motor on the blue and the only thing missing the ground that comes from the ECU ?
I take your point about the circuit not being energised without the engine running.
In other words could this yet still be to do with the temperature sensor?
Iím not afraid to be proven an idiot - something Iíve always known !