andy did you check all the fuses ,i seem to recall that there is another fuse in fuse box that also feeds heater motor but is marked differently-i would check them all! if ok then try running a live feed to heater switch feed terminal .if it works i have known that soldered fuse blade in fuse box to crack around it with heavy heater use. [if very good with soldering gun ,and you are competent you could remove complete fusebox strip it down and repair it] -but you must note where all relays/fuses/link plates fit! just another point ,make sure that resistor pack is ok,think it is fitted near to motor under bonnet. also check motor it self , hope this helps
k, December 2009