Are you looking for the correct Namesevers for Fast Hosts? They can be hard to find!
There are two to choose from:
ns1.livedns.co.uk (IP: 126.96.36.199)
ns2.livedns.co.uk (IP: 188.8.131.52)
AND if your provider supports any additional nameservers you can select:
ns3.livedns.co.uk (IP: 184.108.40.206)
When dealing with Fast Hosts we use ns1.livedns.co.uk.