Re: How about Companies House?
"I tracked down the issue to one of the companies that offers Companies House lookup information on the Internet, which had not only not noticed that the company was no longer trading (nor when it was deleted), but had 'corrected' the telephone number to my home number."
You went about trying to get the incorrect information removed the wrong way.
A DPA section 11 notice works wonders for that kind of thing and after failure to comply it's a simple court filing to wake them up to their responsibilities (If a bailiff is going in to seize things, always tell them to target the communications/networking equipment to take first, not things like TVs. It has a galvanising effect on getting attention to find the most critical piece of equipment and remove it.)