They could benefit from the new Freeview rules and get a fairly high channel number. Wouldn't surprise me if they chose to put C5HD on 5 and bump the SD equivalent down the EPG
along with all of their other channels.
They won't bump the SD version down the EPG, but if the Freeview platform is clever enough to place
the HD version on LCN 5 on HD equipped receivers, then that would be a step forward. (But I don't think it is ?)
Many Freeview TVs, particularly HD ones, allow you to re order the LCNs anyway, I've had the HD versions of all the channels on their 'SD' LCNs for yonks (and BBC News HD on LCN 8 ),