It is repairable. power off, remove back cover, disconnect heater terminals. Unscrew heater mounting nut and lever heater out along with its rubber seal (may take some levering).
Reinstall new heater, ensuring that it slides inside its retaining clip inside the drum (this stops the heater contacting the spinning drum). Ensure that the channel in the rubber seal is sitting fully home on both sides of backplate - a bit of silicone sealant wouldnt go amiss.
Check out my site for info: www.2ndwave.co.uk/manual.html
dan
February 2008