Apologies yes the BBC is now using 704 x 576.
However the file you get is much larger than it needs to be. Breakfast comes out at 2.36 GB. Largely because it contains in addition to the main stereo mpeg audio a second Audio described mpeg audio track plus a DVB Subtitles track. You should be able to strip these out using free software. More later when I have had a play.
The comments re frame doubling refers to using a HD recording as the source and using the webif to download.
This gets you a frame doubled 720 x 576 copy with a lot more potential if you strip out the extra frames to get a 25fps file and use vidcoder free you can increase the resolution to HD 720p resolution.
Playback of the SD files is best done using a UK standard box like a HDR-1000S.
The Aura can be set to output UK broadcast TV at 50Hz . If apps like VLC are used the box uses drop frame to output at 60Hz. Going to investigate to see if output at 50HZ is possible using VLC.
Going to try Tsmuxer GUI to remove the unwanted data.