Just wanted to come back agin to thank everyone for their suggestions. Having gone through the entire house and checked tightened every screw I a happy to report that I think I found the offending thing. Well, in the Consumer unit the Neutral feed from the meter was loose, it took way more turns than it should have, didn't see any signs of arcing, not sure if I would or not but anyway there was none.
Found 3 or 4 really grotty looking connections i an upstairs room and even a live cable just hanging in the wall cavity space. Not terminated or anything, looked like it used to feed an Expelaire which had been removed and the wires just left hanging...Hmmm, not clever.
So, over 2 week now and the TV is behaving.
Thanks
