Belling oven?

The oven isn't heating up on our Belling Compact Auto Deluxe; there are two heating elements, one each side; neither is heating so is it likely to be thermostat or switch? Oven warning light comes on under knob - if stat has failed in "detecting oven at temp" mode I would expect it not to be on as light goes on/off in normal use as elements are on/off to maintain temp.
Is switch and stat one unit or available separately for this model?