Look at this...
several people on your other favourite forum have recently spotted that BBC HD is now full 1920x1080i, as I have. Besides, higher bitrate 1440x1080i will look better than lower bitrate 1920x1080i. It's a compromise either way, but bitrate can often make a bigger difference. It's a complicated subject.
In addition, the Wikipedia article (which is presumably accurate at the moment) does state that Virgin Media has the highest quality feeds of BBC HD right now, with 17Mbps MPEG-2 streams, and that this is about double what some of the other HD channels have (also MPEG-2).