although I'm very pleased to have everything working again, I still have two issues:
Firstly why did it happen, the only time a second box might have been connected was when I first joined talktalk, some 3 years ago and I have regularly watched Sky Arts without problem. Could connecting anything else trigger the problem?
Secondly, why does the call centre not know what TTG-239 is and how to sort it. I spent nearly 4 hours over 2 calls trying to get them to understand the issue and pointing out that problems with my internet connections were unlikely to be the cause as I could watch catchup on iplayer, etc. with no problems. They're final solution was to arrange for an engineer to come in 2 weeks time. The only good thing of all of the time wasted was that, in my boredom, I went on the forum and found the solution myself, I did point out that TTG-239 was on the forum and an answer was available but this was ignored in favour of internet connection problems. Guess I'd better cancel the engineer or I'll get charged for a wasted visit.