Re: Hotpoint BD42 oven/grill
When you say you opened the oven door was this the top oven or main?
Sounds as though an element has blown, usually physically obvious when it takes out the main fuse.
A careful visual examination followed by testing each element with a meggar or multimeter is required.
There is one element under the base of the top oven that you cannot see, side panels have to be removed to access that for testing.
Be sure to isolate from the mains if you intend to have a look.
Jim.