Griff,
The best way I can describe it is that prior to the overheat problem, the fan would come on occasionaly, in say heavy traffic or at the end of a journey, when the car was stationary and the engine was running. It was noticable when it came on as it is quite loud. Now, the fan runs all of the time. I posed the question on here previously and one answer which to my mind seems entirely sensible, was because the ecu had registered an overheat fault, causing the fan to run permanently as a precautionary measure.
No luck with the Nanocom.
Regards
rdw