you could go on the virgin media web site, click help and support
click check service status, put in yours (or another
close by ) post code if your a bit worried and see if there is a local
fault with your internet service. Ive done it a few times
and never had a knock on the door.
Is all your other internet stuff working ?
Can you swap leads on your homeplugs to check if its them ?
Have read the odd post on other sites reporting problems when new hubs have been fitted and
but replys by other say they are in the same boat and it's not the hub.
suppose you can only check what we know as possible faults until there is loads of posts
blaming the hub.
thing is if your channels keep coming and going it may be a server issue.