I'd be interested to know how exactly DNS settings on your pc are causing this and how changing the DNS [on your pc] will solve it.
I don't use NTL DNS, I can resolve
www.google.co.uk fine, but I cannot access it (or any other site) via NTL, if I switch to another (non NTL) proxy I'm fine again. If I put the IP in locally I can access any site fine.
This suggests to me that the NTL proxies are going the DNS lookup (and failing) therefore changing DNS locally will have no effect.
Am I missing something obvious here ?