I use the local I.P. as it's quicker and easier.
I just tried through a proxy and therefore used the domain name and it worked!
Thanks yet again!
UPDATE!!! I found that using the local I.P. was the problem!
If I edit my hosts file on my desktop P.C. (to map the URL to a local I.P. see here
) and then use the full URL (the one all others will use to access my server) it works! i.e. 'http://www.domain.com:81' not 'http://192.168.0.xxx:81'