Where abouts are you in Manchester? I'm in Sale and my NTL has been fine. (I have a Samsung box though) Have you tried turning everything off at the mains for about 15 minutes? Also i don't think it will make much difference, but sometimes when this happens i take out the NTL card. If it doesn't work after rebooting, then i'm afraid your NTL box may bee offline till Monday. Which was often the case with the old NTL box.
I too am on NTL and live in Sale.
Last month I phoned NTL to point out that my old Pace box kept locking up, requiring a complete mains on/off power recycle to get my channels back.
They agreed to swap it out for a Samsung.
I phoned at 1830 on a Friday and the engineer swapped the box out on the folowing Monday afternoon - good service.
Has worked fine ever since with the Samsung box.
Though i agree that you received good service, it took five visits from the NTL engineers before we got the new Samsung box. And we didn't even know it existed. So if i was you Bex - even if this is the first time it's happened in a long while - i would tell NTL that it keeps happening and you've heard the Samsung box fixes it. If they give you bull**** that none are available at the moment, threaten to leave NTL.