There was a "Scan for new channels" menu option which was the first thing I tried (several times), but it didn't seem to find anything.
One advantage of resetting the channel list was that everything did appear in the correct order afterwards, I suspect that if I'd just added the new channels (and it had worked) then there might be still a zombie Channel 5 as the fifth channel and the real Channel 5 at the end of the channel list. It also meant that new channels that have appeared over the past few years like Virgin 1 are now in a more reasonable place rather than at channel 804 as it used to be.
no subject
One advantage of resetting the channel list was that everything did appear in the correct order afterwards, I suspect that if I'd just added the new channels (and it had worked) then there might be still a zombie Channel 5 as the fifth channel and the real Channel 5 at the end of the channel list. It also meant that new channels that have appeared over the past few years like Virgin 1 are now in a more reasonable place rather than at channel 804 as it used to be.