I think you're right DC. I reckon a little counter-top freezer for around a hundred sovs would be worth a go. When funds allow, I'm going to get solar fitted which will also help and the lolly I'll be saving by buying a 240v freezer as opposed to a 12v can go towards it!
Exactly what we did.
Freezer from Argos (£80 from memory) run from the inverter - you can get a lot of 'electric' for the £500 saved by not buying a 12v freezer.