Thx for the reply m8.
I have checked 3 different RF cables with 2 different tv's and its the same with them all
I did explain this to the girl in CS and she said well if your STB works on scart then its not faulty. She said bringing in the RF output into the equation just complicates things and that if I ask for an engineer and its not NTL's equipment that is at fault I have to pay £25.
She couldn't seem to grasp the fact that the RF wasn't outputting the digital signal and said I was just complicating things. And in the end she just said "well it's either your equipment or our equipment that is faulty"
I have arranged an engineer to come on Saturday morning.
One thing I did stipulate at the time of upgrading to Digital was that I wanted Analogue put-through. And the guy that I spoke to when ordering digital said that this was no problem at all ( as long as NTL are broadcasting an analogue signal I will have that capability).
So I have basically deduced that the Set Top Box is faulty and I will be looking for a replacement on Saturday.
One other thing I forgot to mention to the CS girl was that when I noticed the problem I immediately tried a different cable but when I took the RF cable out of the back of the tv it definately had a "current" running through it. I didnt get an electrical shock but it felt like the same voltage u feel if you wet your finger and then place it over both the connections on a 9v battery. I don't know whether this has anything to do with it or not (touching the cable end now does not have that effect). I should really have mentioned this to the CS girl but I ended up being so frustrated at what she was saying I forgot.