Since they have a hub that's older than the hub3 then the account holder should be able to request a free upgrade due to possible security updates issues.
See https://www.virginmedia.com/help/how-to/broadband/device-security-information
The account holder may also be able to upgrade the hub (depending upon the speed of their package) by logging into My Virgin Media. Info below from the following page:-
https://www.virginmedia.com/broadband/existing-customer-deals/hub
Can I upgrade the Hub?
If you currently have a Hub 3 or older model (including the Superhub 1A, 2A etc.) you’re eligible for a Hub upgrade if you order or upgrade to one of our Gig1 Fibre broadband packages.
Sign in to My Virgin Media to check your existing package and upgrade your service today.