I have the V6 box - I have sound on all the channels except when I go to 'on demand'. I thought it was something to do with an old program, but no.
here's the weird thing - when I'm watching (not listening) on demand and I press the 'guide' or 'home' button the sound comes back. only thing is, I can only see the little screen at the top. when I go back to the big screen the sound stops.
Normally I listen through an amp connected to a Bose system but I bypassed that and tried sound directly from the tv - nope, still not working on 'on demand'.
any ideas or has virgin media messed up the box again