Stop and think for just a moment how the oven works.
Power comes in from the wall outlet, which is (or should be) protected by a dedicated fuse or breaker in your consumer unit (fuse box).
It is then distributed to the various rings, ovens, clock.
Thought no. 1: Only the oven is affected. Suggests the supply is OK.
Concentrationg on the oven, power to the oven goes from the distribution point thru a switch (which may or may not be part o fthe temperature dial). This turns power ON to the oven fan and to the thermostat and element.
Fan works OK, suggests switch is OK
The only items specific to the heater will be (possibly) a switch (which may or may not be part o fthe temperature dial), the thermostat and the element itself.
Wich of those is likliest to have failed? Clue: The element spends its life cycling between room temperatire and very hot.
Its probably the element. So long as you can get the correct part (Clue: You'll need the cooker make and model number and search for Ariston spares. You'll probably end up at espares or ransomes or partmaster.
You'll need to stop and thjink through the operation of getting at the element.
DON'T FORGET TO ISOLATE THE COOKER FIRST!!!!!
MAKE SURE YOU KNOW HOW TO SET THE CLOCK AND SWITCH THE COOKER BACK YOT MANUAL WHEN YOU POWER IT BACK ON
No manual? Google is your friend
Work methodically.
Use a pencil & paper to record where screws, bits and pieces and which wire goes where. Use labels too. DON'T RELY ON MEMORY
IF IN DOUBT AT ALL CALL A TECHIE
XXXX, April 2016