I've spoken to BT and emailed, in their response they assure me that it isn't blocked, nor do they block any sites. For some reason they think I suspect that they are blocking the site - despite my entire email stating I think the problem is something else.
They've offered to ring me so I've asked them to do so tomorrow and hopefully we can resolve this then. If anyone else wants to send them my way i'll be more than happy to deal with them.
So what was the problem? i.e. what was "something else"
ps I e-mailed BT and they denied blocking and gave out the pish that they give out while avoiding making any effort whatsoever to investigate the problem.