One other bit of possibly useless advice I got from a fridge/freezer repair man.

Apparantly the flow of the liquified gas in the heat exchanger can become blocked resulting in inconsistent temperatures. He said it was alway worthwhile standing the fridge/freezer on it's top for a while and then putting it the right way round again. Not forgetting to let it settle for 24 hours before you plug it back in.

Costs nothing - May help.

Cheers

DtG