When I now put the heater on I get a clicking noise which increases in frequency as I turn the power of the fan up. Anyone any idea what this could be? It's starting to get very annoying.
You probably have a leaf in the fan. My Mk1 used to suffer from this because I had to park near a willow tree and those thin leaves managed to find their way into the fan all the time. Putting the fan on full for a while usually blew it out of a vent but it sometimes took a while.