What I'm about to suggest is a shot in the dark but might be worth checking.
Have you allowed FFXIV through any firewalls you have, including Windows Defender Firewall?
90002 happens when you have a unstable connection to the game server but can also be caused by firewall's interfering with the game connection.
Try allowing ffxiv.exe and ffxiv_dx11.exe through any firewalls you have and re-login to the game.
If it still persists after you've allowed the game through any firewalls then the problem 100% is with Virgin Media's side of things and good luck with getting that fixed.
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Previously M200 (Left due to utilisation)
Now: BT FTTP 900/110 connected an ASUS RT-AC86U router.
https://www.speedtest.net/result/12098955842.png