2/ RTFM.. Read The Flip'n Manual.. the Internal IP of the Modem is there
Undies, this is a USB /ADSL modem specifically made for and supplied by British Telecom (the ISP). It doesn't have a manual It has a dynamic IP addy supplied by BT, whenever you login.

IT IS INTENDED TO CONNECT ONE MACHINE at any one time to BT's ADSL service. You are not supposed to use it for networks. If you want a network you are supposed to subscribe to one of the commercial/SOHO plans..................and pay them more money

As BT run their domestic service with a contention ratio of 50:1, it is not surprising that they do not like networks being attached to the service.

I think that mrmoz should check his TOCs before proceeding too far.

just a thought