Thanks to all for the feedback. Nick that's a good suggestion about checking the matrix on the back of the fridge as I haven't done that yet. The unit is 12 years old and the door seals are in good condition -- bear in mind that it only gets used between 8-12 weeks/year. The bottom of the freezer compartment gets pretty cold but nowhere near the point that it takes the skin off your fingers.
It's a bu**er troubleshooting a system I know nothing about, so just for clarification;
Regarding the loss of gas, if the system is sealed is it really possible to lose just "some" gas, but retain sufficient in the system to get some cooling affect without it all leaking away? Similarly, if the problem is with the compressor itself, would it likely to sound any different from when running normally? Everything sounded "normal" to me except for the fact that it just failed to shut down.
The other thing was that it was pretty hot on Friday and the cabin temp got up to 26C, but even so the fridge would normally have caught up to its regulation point within a couple hours.
I think the next step is to give the back a good clean-up and check the ventilation then give Shorepower a call if there's still a problem.
You can't get away with a staement like that Come-on, spill the beans.
Another general question: assuming my fridge is actually knackered, what alternative 12V models would come recommended? I think there was a similar discussion not long back, but things/opinions might have changed a bit over recent months.
Thanks again.... Weeble