I gave them a call to give them my 30 days notice today (4 pm), as I'm moving to a non-NTL area. I advised them of my moving date (in two weeks time), and the nice lady on the phone asked me when I wanted my STB to be collected etc, so I set that for the day before the move. The email addresses will remain active till the end of the month, when my payment/subscription stops. She also told me that my phone would be restricted, which is good I suppose.
However, I was expecting the restriction of phone services to take effect in two weeks, not 4 hours time...
I noticed at 8 pm that I am no longer able to make calls (though I can receive them). I just get a continuous tone after dialling 4 digits. I supppose a call in the morning will sort it, but IMO it is a bit silly to have phone restrictions in place 4 hours after giving your 30 days notice, and told them you will be moving in 2 weeks.