Come on guys it doesnt take much intelligence to work out the legalities of this.
If NTL provide equipment it is not subscribing, when you subscribe to something the company does not get it back. It is gone. Subscribing you have it once, examples subscribing to magazines and tv channels. You dont return the magazines at end of subscription and you cannot return watched programs either.
The equipment is defined as 'loaning'
http://www.thefreedictionary.com/loaning
"loaning - disposing of money or property with the expectation that the same thing (or an equivalent) will be returned"
I expect that NTL used to charge for modem rental etc. and they do indeed charge for things like 2nd boxes but by making it free they had a way to not use the word hiring, but I think you are still effectively hiring the equipment but its cleverly buffered in the price.
The document ian showed has no argument against it, if it clearly says hire agreement then thats what it is. I will try to dig out my contract which is from august 2003.