I'm also in the UK and have just set up an upright freezer with a temperature controller as a cheese cave. The controller I bought on ebay was a "Mini Digital Temperature Controller Thermostat WH7016E" for about £15 with free delivery in the UK. The cave has been running for just over a week now, keeps the temperature with about a degree of my target 11 C, and only switches the freezer on for about 2 minutes every half an hour or so to do so. I'm absolutely delighted with it.
Hope this helps