Hi @Anonymous User
I am assuming there is no sound from none of the Apps on your NowTV box ?
Sounds to me you have tried most things that i would have tried myself in this situation.
Have you tried a different HDMI cable and HDMI port on the television ?
Also go into the Television menu and have a play around with both the Sound & HDMI CEC settings.
Maybe also go into the NowTV box menu and again play around with the Audio Settings (start with Stereo and work your away down the list).
Make sure when you swap HDMI cables or HDMI ports that you switch the power off at the mains outlet socket to both your Television & NowTV box.