A friend has a Logik model LUL55S10 and the light comes on OK and the motor is warm and makes a little noise but the fridge isn't getting cold, was b rought in 2011 so not exactly old.
I'm guessing it could be the thermostat which seems to be about £10 but c an't find a suitable motor/compressor if needed.
I can pretty easily test a themostat and replace it, but not sure how to 't est' anything else.
So any advice gratefully recieved.