Presuming the Virgin hub is still doing the GRE tunnel you would have to manually assign one of your static IP's to the WAN interface on your router.
On most consumer routers this would be done by disabling DHCP on the WAN interface and setting the static IP address. This could be any one of your static addresses from Virgin. Virgin should have given you the Subnet and Gateway to use if memory serves me correctly.
You would have to read the manual on your "Zen WiFi Router" to see if / how it supports multiple public ip addresses on the WAN interface. A basic consumer router might not.
You can make use of these with
pfSense as your router / firewall, one such example how to here:
https://bobcares.com/blog/pfsense-multiple-wan-ip/