Assuming the upper element is supposed to come on when using the oven (broiler?) and not just for the grill, the element itself may have failed.
Easy enough for someone competent with electrical appliances to check safely.
If the cooker relies on the top element as well as the lower, that may be why the bottom element is working hard.
Is the circulating fan inside the oven working properly?
It could also be the oven control switch or the thermostat. Again, should be easy enough for someone competent with electrical appliances to check safely.
You'll have doubtless come acroiss spares listings and diagrams online when you did your own search to solve the problem. In case you missed some useful results try:
https://www.zzzz.co.uk/diagram/rosieres/cookers-hobs/894777/4040db%20(39342340)/
and
https://siteassets.zzzz.co.uk/ModelDiagrams/39342340.pdf
For some reason this website doesn't like URLs with "ransomspares" in them so replace "ZZZ" in the above addresses with "ransomspares"
qweqweqw, July 2018
