Smeg Oven A2BL-6 won't heat up - SOLUTION

I had a problem with my Smeg Oven, model number A2BL-6. For no obvious reason the oven would not heat up. The power was OK, the light would come on etc but the heating elements were not getting hot.
I thought the thermostat must have given up but then I fiddled around for a bit and managed to figure out that by turning the main over contral knob anticlockwise, rather than clockwise how I normally turn it, the over works fine.
It's a bit a niche issue but if watching this saves you spending a few grand on a new oven then that's great!