Although the restore procedure handles services (channels) that have changed details while keeping the same name, it doesn't deal with something like "Channel 4+1 HD" disappearing, where one might want to substitute plain "Channel 4+1". A further step could be added to check for a channel with " HD" removed (or added, if it wasn't there), but (a) although that would be straightforward for favourites, it would be quite tricky for events (which SD show corresponds to a certain HD show?) and (b) the horse has bolted.