I'm having the same issues, screen freezes on SD and HD channels, can't operate the V6 box. Frankly finding the service quite useless at the moment. System tests show everything OK but it's obviously not!
It happens on all channels but not when watching Netflix and Amazon Prime. The screen does not freeze, I think it may have to do with the connection at the wall socket as you push it in, it is loose in side, it is like you are pushing it in and whatever is in the box moves up, so it feels like it is not connecting properly. the wall socket is very old was installed before I moved here and that was 16 years ago.
I hope you can help as it is becoming very frustrating and it is very hard trying to phone Virgin with COVID restrictions in place at the moment. It is not the service I expected from Virgin when I signed up.