It sounds like the thermostat's bust.
Easy job to fix.
You will need to buy a thermostat kit (you should be able to find an outlet in the yellow pages) the number of the part you require is 1701583.
Unplug the machine. Take off back panel and you will see the two thermostat components.
Take note that one of the components has a green dot on it.
Replace the two components.
Replace back panel.
Finished.
PS In Edinburgh the thermostat kit cost me £27.
Andy Goodall, Edinburgh
January 2006