I 'reset' it by turning it off and back on again via the control panel at the back of the Fridge compartment. It then works for about 8 hours or so before turning itself off again.
The control panel has a small box behind it which contains a PCB manufactured by Ipotesi and labelled 'R20'. It has three wires coming out of it labelled 'CV1' (Brown wire), 'CV2' (Black wire) and 'CV3' (Blue Wire).
I believe that two of the wires run down the back of the machine to the compressor. I'm not certain what the third does.
I still can't find a defrost timer of sorts and I'm still uncertain how to go about identifying let alone rectifying the fault.
As ever, any assistance is much appreciated! If I can't get this sorted I won't be buying a whirlpool again, probably a Samsung!