I'm going from problem to another!
The (middle paddle) fan heater slider has become stuck with the fan on.
I removed the glove box and clock and can see the fan cable outer has come out of the spring clip that holds it in place.
There seems to be one screw holding the heater control facia in place to the wooden clock housing - that screw needs to be removed from dashboard side.
Do I need to take the whole dash out to re-attach the cable it or is there a simpler solution?
In the short term I moved the heater fan to the off position manually in the engine bay.
Thanks again.