No start / end of set-top box and home theater at the start of the XBOX One

I think it would work if you remove the SCART cable between the Virgin box and the TV, and move the other SCART cable going to the home theater system from the Virgin box directly over to one of the SCART inputs on the TV.

Check the cables to see if they have any labels on the connectors. If one end is labelled "TV" and the other "DVD" or similar, it's wired to carry signals in one direction only. If you have a cable like that, use it between the Virgin box (DVD labelled end)
and the home theater system (TV labelled end), and the other cable between the TV and the home theater system. If both cables are labelled this way, you need to pick up a fully wired SCART cable to go between the TV and home theater system.

Connected that way, the DVD player will input picture straight to the TV instead of going through the Virgin box, and the sound from both the Virgin box and the Xbox 360 will be sent to the home theater system back through the SCART cable.

If this works, then leave Dolby Pro Logic II enabled for both games and TV - both will benefit from it.

Hope that this helps.

Setup is here:
support.xbox.com/.../connect-console-to-home-theater

Go here:
support.xbox.com/.../poor-audio-or-sound-quality

Audio settings are here:

support.xbox.com/.../configure-audio-settings

***surround sound may be limited to a set top cable box...as I tested my PC which does send a 5.1 signal and the Xbox one is not able to decide from my PC to hdmi out of the Xbox one to the stereo. My cable box does send surround sound depending on the
channel.

The way the One works is you put it between the upstream end and downstream end and it works with the set-top box. If the "set-top box" is downstream I doubt it works.

G'day Mandy. Sounds like you're missing the set top box from the equation. Currently, your console is sending info to the TV for its own features but it doesn't sound like it's receiving the information from your TV provider.

Check out the steps here to set up your console for Live TV.

Perhaps there was an accidental error when the TV was connected to the console. Check this link to see if everything looks good on your end.

support.xbox.com/.../connect-console-to-home-theater

Then here's another guide on how to adjust your settings.

support.xbox.com/.../set-up-live-tv