Fridge Freezer single or twin thermostat?

[BBx]

Hello!!! Wonder if anyone can help me with this one...?

I need to get one as its been months since the freezer in mine has broken... the fridge still works... but have been looking at the sales and the only thing troubling my decision is the single/twin thermostat thing.

I don't really know what they are, and of course the people in the store are complete noobs and know **** all about what they are selling.

Can't find anything on the net explaining which is better or how it works... so if anyone finds anything thats great.

I thought twin thermostat meant that one ran the fridge and one ran the freezer, so if the freezer one packed up the fridge would still work (which I am assuming has happened to the one that I have now)... but from what I found on interweb, the thermostats only control the temperatures of each part individually and nothing says that it controls the running of each bit.

There is about £150 difference between the two I have looked at.. £150 I could use elsewhere really... but am a bit torn :/

I'm confused!!! please help!!!

BB x