If I set audio settings for the box to PCM, then I get sound on Netflix ( and everywhere), but in Stereo, not in 5.1. So while this gets me audio, it's not really a solution - it gets me the same result as if I were on Dolby settings, and if I set Netflix to regular audio. I guess I'll continue using my AppleTV for Netflix for now.
Any updates to this? Just checked and still no Audio when it's set to 5.1. Shame Virgin is not updating and fixing glitches. Though not surprising from Virgin Media, I guess, given we are already signed up. If we were prospective customers, they would promise the world and even offer to fix it!