I had pinged via wireless and results were fine which is what was so confusing.
However.....I managed to fix it, some how! Pulling at straws and thinking it was a networking issue I downloaded a TCP optimizer program which changed the MTU settings and also a couple of others for the laptop on the network and hey presto - all working again!
http://www.speedguide.net/downloads.php
Thanks for all the suggestions and hope this might help someone else