Hi, I have an ancient Ideal e type boiler which works well, except the thermostat is considered to be a bit "iffy" as it does work but not with reference to the numbers on the dial. I managed to get a replacement genuine thermostat and am awaiting someone to come and fit it. He is a young man has the certificates and seems keen but I am not sure how knowledgeable he is about fitting this thermostat from what he has said already. Is there anyone out there who has the knowledge of replacing this thing that could be passed on to him?