This is from a Whirlpool for IKEA fridge freezer which is about 16 years old, but the serial number is recognised by at least one online spares supplier which it uses to identify a replacemen5 thermostat. (The serial/service number is 853976215051).
Having read Lafite’s comment I persevered, as I am quite sure the thermostat knob cannot be pulled off on this model either. Eventually after giving up a couple of times, but finding no other solution, I did manage to release the moving plastic light switch at the front. This revealed the screw (pictured) which I proceeded to remove with a great sense of triumph. Imagine the deflation therefore when no matter what I try and how carefully I investigate, and despite checking all around to be sure the thermostat housing is not clipped into the fridge side, it is still solidly held to the fridge. No amount of manipulation, squeezing or attempts to slide it have any effect.
I am wondering if the tops of these appliances are removable and whether there is a screw or two accessible from above, accessible down the side inside the inner side wall, which would release the thermostat, which is near the top of the appliance.