I have checked with my service provider and they say they do not block that site, and the website administrator also confirms that they are not blocking me.
I downloaded anonymizser to run one my home pc and this enabled me to connect to the site so it is my internet ip address that is the problem.
I have checked all my router and computer firewalls, and I don't have any.
I run AVG 2013 ANTIVIRUS on all machines with their firewalls deactivated.
AVG have looked at it and so far cannot figure it out.
My IT consultant cannot figure it out.
I am at a loss what to do next.