IIRC, Virgin hubs have a modem mode of sorts, but I don’t quite remember if this completely turns off routing and wireless or just wireless, so this could cause a double NAT issue.
But when I was with Virgin the best experience was always achieved through using my own equipment in front of the hub to interface with my devices. This was the only time I’d ever achieve their advertised speeds.
Even their latest hubs at the time were rather meh. They’d always find an excuse or something else to blame. It was never a fault of theirs or their equipment, it was always an issue with my equipment, according to them. But I’m not your average Troubleshooting Tom, so I knew better. Swapped to my own equipment and eventually left.
I do miss the speeds some times. But I don’t miss the qos.