Hi there,
I am not sure but have you checked the connections to the resistor at the back and the earth? Both of mine caused me to think it had failed, when it hadn't really....
The resistor is behind the heater and should have a connection at either end.
The earth is a "fly lead" from the heater to some point (mine was a ring connection between the heater casing and had rusted).
Hope that this might help!
Otherwise Brands Hatch Morgans / Melvyn Rutter could be a good place to start.
R.
