Secondly, why not simulcast some of the HD programmes from BBCs 3 and 4 evening schedules to fill in the (seemingly vast quantities of) empty air time (rather than a continuous loop of just a few seconds of upcoming, or past, events)? It shouldn't be too difficult to select which of the channels is showing a programme that would benefit from an HD version and making it available via the button (advertising it in advance on the TV guide to maximise viewers).
Finally, I'm told that it's not technically possible to get 5.1 surround sound on the Red Button HD channel. I'd just like to say that's a shame.
(PS Trev, above, perhaps you should take that up with SKY - or cancel your subscription and buy a freesat receiver).