Thanks for your fast reply and sorry for my slow reply.
Problem got sorted out.
Last year I could not get Location: to work on one of my computers. I think IE was garbaged.
I thought I had the same problem this year when I tried out Phorum.
However on investigation I realised they were using a variable for the address, and that the server name changed when I was viewing from Internet as opposed to from the server itself.
Thanks Vincent anyway for your interest.
Paul