Hi Mark, this might come too late for you, but perhaps may help others with the same issue.
I had the same problem and initially I replaced the wrong thermostat....I replaced the thermal cut out (TCO) which looks very similar.
The fan cooling thermostat is slightly different: for my model (S20 MX1) it was this part from shop.ukwhitegoods.co.uk -
https://shop.ukwhitegoods.co.uk/818731204-cooling-fan-thermostat
(NOT the Safety Cut Out thermostat )
Hope that helps others who might have a similar issue
Paul
October 2021