I have one of these cookers which has given good service over the years. I now need to replace the thermostat and have the manufacturers agent (Hoover Candy) coming on Tuesday. Unfortunately, they do not know a rosiere cooker from a hole in the ground. This will be his third visit spanning a month and I need to know how to get access to the thermostat as the engineer hasn’t got a clue, nor has anybody else in his organisation. HELP!