[Paul]

Ring them and tell them you are interested in taking their services but cannot justify spending more than £10 per month and ask if there is anything they can do deal wise as you have been told that you can get a 2Mb service on ADSL for the same money but would prefer to use NTL.
Do you have any services from NTL at the moment? If you are paying for the connection I can't see the problem but i'm guessing it's your parents paying.