we came across the same problem and comet despatch several of their esteem engineers out to fix problem after several visits they were unable to find fault in the end we gave up until the last engineer they send put us on to a company who does the London and surrey postcodes www.agsrefrigeration.co.uk. we were a little surprise to say the least but we decided to give them a call they came out the next day and found the fault which was something to do with some kind of baffle in the fridge compartment its been over two years now and our fridge works just the way its supposed to do. If you are in london give them a try.
Fred
January 2013