To highlight
If you move to the Hub 5,
your old Hub will no longer work as the router has to be registered to the network, and by moving to the Hub 5, the old registration is no longer valid.
You can argue with Virgin that you want to go back, and that you have the old hub,
but there is no guarantee they will let you, or how much time / money they will chare you to go back.
I had this with the Hub 3 v Hub 4, 4 is a step back for us , but despite many many may phones calls / emails / even good old letters, was not allowed by virgin to move back to the 3,
After all, they have no reason to ,
they have you as a customer already,