Your V6 boxes all link to your homehub for OnDemand & Multiroom streaming - not directly to each other.
If your hub has been swapped, it sounds like none of your V6 have a working internet connection.
I would presume that they're using WiFi except one might be an Ethernet cable? Or all using WiFi?
In either case... Home > Help & Settings > Settings > Network. You'll need to reconnect any box in here, that's not got a direct Ethernet connection.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks