I have signed up for Virgin Media and had the install yesterday. Everything has now been setup, however I have found that when trying to watch 4K content within the Netflix app on the V6 box, I am given a green screen and then the message "Netflix encountered a problem, try again later".
I have a 4K TV and able to watch the content via an app on my TV, or on my Xbox One S so I do not believe the TV is the problem.
All of the above mentioned devices have a wired connection to the Virgin Hub 3 router.
I had already tried the resolution settings, with my TV already being setup on the V6 box as 2160P.
Strange thing is that this seems to be intermittent. Following your message I attempted to watch Daredevil and it worked fine. After the one episode I turned off the V6 box, then later on attempted to watch the next episode, however that one gave me the green screen.
It seems like this, the ongoing issue that my area is having concerning On Demand services, the V6 box randomly resetting during certain shows and the latency issues on the SH3, I am starting to regret my move over to Virgin.