I have the same problem over about 170 degrees.
The grill works fine. I'm pretty sure that you need a new element for the fan oven. It is circular and located behind the back pannel inside the oven.
I replaced my element last year after the original gave up on me after 8 years. I bought a cheap replacement from ebay and it appears that it it was money down the drain. Basically the element wire is heating up then expanding as it does so. Eventually, (this is my theory), the wire expands and touches the metal casing that it is housed in, this in turn trips the safety trip in your consumer unit, (fuse box).
I have just come to google the element to buy a DECENT replacement, (with a guarantee),....not a cheap one.
Make sure you have the main oven switch off at the wall or consumer unit before you take the screws out for the back pannel. You may need a torch whilst you are in there. The element has two terminals with spade connectors on. These need to be prized off but don't let them fall through the hole at the back or it's a nightmare job. The element can be unscrewed and replaced. Get someone to give you a hand if you are not confident to do the job. It's simple enough providing you take your time and are safe.
Ray., January 2010
