Resetting the autocut-out in an old Dimplex Convector/Night Storage?

I've got an old Dimplex combined Night Storage & Convector heater. Only the convector bit works at the moment and I can't find the model no. as its been painted over. I'm assuming it's been covered at some stage and the 'autocut-out' has switched the Night Storage part off. This heater is definately over 12 years old. 4 questions: 1. How do I find the model no? 2. Can I fix this myself? 3. Where do I get the parts from? 4. If I need to get an expert where should I go in London W12 (I'm looking for a job at the moment so cash is tight) Many thanks.