These web addresses go to exactly the same company:
http://www.martindawes.com
and
http://www.martindawes.net
Both websites state (under 'Terms and conditions') that the registered company name is 'Martin Dawes Limited'. Despite the lengthy history shown on the 'About Us' page of that common website, Companies House records show that Martin Dawes Ltd only came into existence on 5th May last year, 10 months after Martin Dawes (TV & Video World Ltd) ceased trading. It's likely that the liquidator sold the remnants of the old company (including their customer database) to the new one, which would explain how they've still got your details. (However, if they've not got them for any valid purpose - such as honouring any warranty agreements made by the old firm - they're almost certainly breaching the terms of the Data Protection Act by retaining them).
Regrettably I think that you'll either need to find a decent TV repairer (which can be hard in these days of 'throwaway' products) or to buy a new TV set. However it might be worth contacting the manufacturer, in order to see whether they can offer any assistance to you.
Chris