Thanks for the help, Phil, but I have to add that I know my heater is faulty, have removed the old one but cannot get the new one in on my Hotpoint. It's just a case of not knowing the serviceman's trick to easy fitting! The seal just keepes compressing and won't go in. I mention this just to show one can know what's wrong without being able to effect a repair.
Smiling Carcass, December 2009