Many thanks for the reply. The server we use is a dedicated server which we set up ourselves inc OS and control panel. Just seems very odd that every other tool is working fine etc but moz won't. I cannot see how it would need anything special from, say, Raven's site crawler.
I will check out those other threads though to see if i missed anything, thanks for the links.
Just checked port 80 using http:// www.yougetsignal. com/tools/open-ports/ (not sure if links allowed) and no problems there.