I have the same problem - and the same potential cost! Trading standards tell me that goods should be good for a reasonable period (Sale of Goods Act 1979 (amended by the Sale and Supply of Goods Act 1994). In your case of 3 years (28 months in my case), I don't believe this to be reasonable. I would expect 8 - 10 years on such an appliance. Try speaking to Trading Standards and get a case Reference Number, then call the trader, explain the situation and express your dissatisfaction (politely). If no joy, put it in writing. If still no joy or no answer, refer back to Trading Standards and they will take up the case. I have found that a warning that you are dealing with Trading Standards prompts some action, but get your facts straight with them first. Hope this helps.
Paul
January 2009