Sorry catmambo, but I didn't see your PM.
However, I am delighted to say that after 12 months and hours and hours of frustration, I have found the problem.
It appears that my Belkin router is the problem as it is not compatible wih Sony TV's, or vice versa.
Even though the Bravia was showing in the routers browser it was not playing ball.
I have now installed a Netgear router and everything work fine.