I've got a DVR-530H working fine with NTL.
You don't say whether your problem is
A) You can't get Guideplus to download the listings for your cable channels
or
B) You can't get the G-link cable to change channels on the NTL box.
If your problem is A), then you need to
1) Set up the terrestrial channels
2) Enter the guideplus set-up
3) Tell it you have NTL
4) If BBC1 is channel 101, then you have NTL Langley, if BBC1 is channel 1, then you have NTL Bromley
5) Tell it the make of your cable box
6) It should then try to change channel, on the cable box. It will try a couple of dozen codes, until it changes correctly.
7) Tell it to download the listings from ANALOGUE ITV (not cable ITV)
8 Leave the Pioneer on standby overnight, to download the cable channels
If your problem is B) then you might need a red-eye converter to get the G-link cable to work
www.redremote.co.uk