Its the fuse. Same problem same period of time, typically just out of warranty. (Obviously turning off the power first) Remove back panel of whichever side of the oven has stopped working and you will find a circular fuse on the right of the cavit. Replacements can be obtained from local electrical suppliers normally as a kit. Mine cost about £21 + VAT. Just disconnect the old one and fit the new in reverse order and fit it back into place in its holder. Easy job even for a basic DIYer. Much cheaper that getting an engineer out.
Steve B
June 2012