James,
to CF.
Firstly, the ethernet cable from the BB Modem should be connected to the 'WAN' port on the back of the router, not one of the four LAN ports.
If you connect this and a LAN cable from one of the LAN ports to the PC, you should be able to browse to
http://192.168.0.1 (user 'admin', blank password) and run the setup wizard - although afaik the defaults should work with NTL. Quick Install Guide
here
HTH