I have a Durabrand CG5660-M Freeview Set Top box. It is working satisfactorily with the exception that 1 (ONE) channel appears with a key when using epg facility and there is no sound or vision available. The channel is UKTV Gold on channel 17. The book shows a key in place on two of it's diagrams but does not tell the user how to remove it (Unlock the channel!). Any suggestions?