I dont think I would want to rely on NTL to bring out the PVR, nor the quality or features of it. They will probably include some sort of DRM, so you can not keep movies for more than a few days.
I am building myself a MythTV box instead.
www.mythtv.org.
It has a large user base, including NTL users. It does however cost a bit in hardware and time. Building one from scratch probably will set you back £3-500. But if you can scrounge kit from an old pc then not so much.
And you may have to pay £15/month for another ntl box if you want to record/watch two programs at once. ( Or gamble on a freeview card .. ). I wont do that as with +1 channels there wont be many clashes. Or build several boxes for simultanious usage.
It does leave you free to user terrestial/freeview/cable or sky with it thu.
ivar