The TV is a Samsung UE50H, connected direct to the V6 with HDMI cable.
Both the TV and V6 box are connected to a wired ethernet.
I have now managed to get it working by changing the video output from 2160 down to 1080 - however, this has not been changed before and I presume has always been working on the 2160 setting. If I let the V6 box autoconfigure it chooses the 2160 setting. TV works OK and the playback of recorded My Shows but the demand just wont work anymore at the 2160 setting.