Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Sticking rev counter on modern 4/4

HI. I have a three year old 4/4 and from new the rev counter sticks at the idle speed 50% of the time when I switch off. Neither Life's nor now Beamish Morgan, with the help of the factory have got to the bottom of this. Purely by chance after all this time I have discovered this evening that it only does it when the heater fan is on when I switch off. Has anyone else come across this or something similar, and most importantly has anyone got a solution I can suggest to the dealer and factory???
Cheers
Derek