[Rob]

I am not aware of any legal requirement to only give a specific number of days notice - no more, no less. That would be unreasonable. A minimm perido of notice, yes that's fine, but if you want to give more warning of something happening in the furuter that's got to be OK.

Thus just give ntl notice now, that you wil be terminating at the end of your 12 month period. If they don't want to accept it, that's ntl's problem, not yours, just follow your phoned notice up in writing (snail mail recorded) so they can't deny having it.