the answer is not easily & not legally.
what you are currently getting are the unencrypted analogue channels that your tv can tune in.
To get any more you need the decoder and the only legal way to get one is to subscribe to NTL.
I'm sure the mods on here won't allow discussion much beyond that, but suffice to say that any STB not supplied by NTL is still their property and if you obtained one you would be handling stolen goods.
- sorry
