Cant ever remember the SD variants being encrypted but the HD channels were at one point FTV as opposed to FTA.
FTV = free to view but still required a valid card even a disconnected one.
FTA = free to air. Like the BBC channels.
The same applied the most if not all the CH5 channels and the ITV 2,3,4 channels etc etc. Most of those channels have not been placed on FTA but some do still transmit FTV.