I can see that the links have been deleted, hence why I'm asking if a more recent firmware version. If there was automatic firmware updating, why is my firmware version lower than the V22.1.00.25_VG linked to above?
I appreciate the router is end-life, but would be interested to know if the firmware version was still available even if upgrading would void any warranty.
The old hubs no longer supported on firmware updates. You should contact Customer Care. Ask them upgrade you to the last Virgin Media, modem/hub I'm aware these are no longer supported end-life. The process on Virgin Media modem/hub on the latest hubs are automatic. The old hubs didn't support this and upgrading firmware version if done incorrect way would break the device. So Virgin Media, teams pushed for automatic updates on the newest hubs.