Well I thought it was fixed, because after the following the instructions I went to the Challenge channel and 15 to 1 was on (a show I don't normally watch), and it appeared correctly. I came back here and crowed my success.
Then watching recordings of, for example, Family Fortunes and Wheel of Fortune it was still improperly proportioned, so I thought maybe it was just my recordings. Today I managed to get an opportunity to watch Wheel of Fortune while it was being broadcast and it was also improperly proportioned then.
Could it be the older shows recorded in 4:3 or something simple like that? It appears so to me. I apologise for the false 'eureka', I am still plagued by the same problem and would appreciate a solution. It's frustrating to not be about to read the things that pop up at the bottom.
Also, I don't know if this is related, but I think not: Every few weeks what I'm watching will go completely black and silent, the menus work, but the channels, recordings and previews are just blank and I have to power off my box (standby doesn't fix it) and power it back on. I get 'Starting up' for 4 minutes or so until everything is back.
I managed to get through to cancellations about this issue and they have offered to come and fit a new v6 box. It is clearly a software bug on the tivo box introduced sometime late september. My parents have a tivo box installed 2012 which has also developed this issue from late sept.
Apparently, it only happens if your TiVo box is connected via HDMI but if it is connected via scart then the problem doesn't occur. Still really annoying. Especially as it has only occurred in the last month or so, so it's clearly something that has happened at Virgin's end.
They sent a new box (the newer version) and we don't have the problem anymore, the channel displays as intended. So seems to be a compatibility issue with the old-style boxes. Still seems strange that it was only a few shows on one channel... Oh well, fixed now.