The element on our B1861blew, I replaced it as normal although this time the element they sent was 2400w instead of 2300w. The oven is now overheating, I assumed it must have been the thermostat but I have just gone out to the kitchen and found that the rapid heat is on even though the oven is switched off! The rapid heat light is not on but the oven is very hot and you can hear the element switch off when the main power is isolated. Any ideas what has gone wrong?