Thanks Malc, much appreciated.. I received your comment in the spirit with which it was sent.
The OP asked for our thoughts and I gave him mine. For the avoidance of doubt and misunderstanding in what on the face of it is an extremely sad situation, whereby a considerable sum of money has been spent in good faith on what turns out to be a less than satisfactory product and the provider has washed his hands of the problem, I would have no hesitation myself in pursuing the matter via the small claims track of the County Court.
The OP having exhausted the option of asking the provider to make good, should in my view seek the only remedy which appears to be available to him. He would be would be well advised to seek assistance from Trading Standards, CAB or a local Solicitor.