Well, this'll save me starting a 'my cooling fan fuse blew' thread of my own. At least now I know the high temp warning light works
So far what I've done is:
Removed fuse, disconnected fan motor connector, checked for a circuit between the fuse holder (fan motor side) and earth (battery -ve) in case there was a short circuit in that red wire. - Result OK
Ran engine up to 90 degrees+ and checked circuit between blue/white wire of motor connector and earth, open circuit <90, circuit made at >=90 approx - Result OK.
Perhaps this is over simplified, but it seems to me that the wiring to and from the fan is in order. So the fan itself must be the problem.
The next problem is do I get a s/h one at £60 and stuff it in and hope for the best, or get a new one, though to do the job properly I really need a new radiator as well and whilst the system is drained I might as well change the thermostat which is beginning to show signs of failing, oh, and better do the rad hoses as well.......