Had the switch to full regional HD today for BBC1 HD South on the Oxford transmitter and box asked for a channel rescan at lunchtime.
All BBC1-HD recordings in the schedule were then invalid in the channel box and empty so had to delete them all and re-add them. Had to delete them first as series link didn't seem to work on the new reservation without doing that.
Probably worth checking your schedule if you are in one of the areas changed today.