Just a quick update. After some difficulty, I managed to get the Pi up and running. On my first attempts, each time I enabled Piholes DHCP Server and disabled the Routers (Hub 3.0) DHCP service, I'd lose all connectivity. No new dynamic IP leases were being issued.
It seemed the only workaround was keeping the Routers DHCP Service Enabled but restricting its DHCP Range to 1 IP. That IP is that of the Static IP issued to the Raspberry Pi. This workaround isn't perfect as there is limited DHCP Lease Time of 604800 seconds set by Virgin.
Does anyone know if there's anything I may have been doing wrong? Has anyone else got Pihole up and running correctly without this workaround?