Honestly, you aren't missing much if you don't see Router Advertisements on the WAN side, based on what is known it's been lurking for a while and you don't have any real ability to use it properly. You can technically assign yourself an IPv6 address within the routed prefix you see (not the managed network one), but honesty it's not really useful, it works but you literally just have a single IPv6 address, no prefix delegation through DHCPv6 etc, it's not really meant to be used. You could go really creative and start trying to essentially force the prefix to be announced with your own stuff, but realistically, it's not meant to be used so there's really no point. The only real interesting point is there is in fact a working IPv6 network "live" in some places, but again totally useless for using it practically really, but one of those "cool, I did a thing" scenarios.
It is quite possible what is visible is part of the DS-Lite implementation, which goes back to 2018.
From conversations back in 2020, it suggested that Liberty Global had basically got an IPv6 network ready and the evidence that's currently live on the WAN side suggests it might still be silently running in the background but even they had issues convincing people (likely higher management and numbers people) within Virgin Media to allow them to deploy it and it seems that still may be the case. So when Liberty Global network engineers can't get sign off to turn it on, there's really no hope for customers having a voice on it, but we carry on trying anyway.
I'd hope due to the lengthy delay and no change since the 2018 DS Lite trials they are at least considering or have tested other options outside of it. Maybe DS-Lite flagged various issues that made them rethink, dual stack seems safer overall despite maintaining two protocols, if the service doesn't support IPv6, it will just use IPv4, if the service supports IPv6, it will use IPv6, great. Given Virgin Media has been on legacy IPv4 ages, maybe users were tied to IPv4 port forwarding (which is possible with the provided CPEs) so they decided not to, complete speculation of course, but you'd think with evidence of an IPv6 network present, it would of been turned on by now, given it's now been 4 years since the IPv6 trials.
Ireland is under the DS Lite by default configuration (certainly for new customers, but older many not have it), however there's a couple of important differences compared to the UK
1. The Ireland operation was formerly UPC before Virgin Media
2. The network from the merger is likely different
3. The network is significantly smaller than the customer base of the UK and therefore would perhaps have more issues with IPv4 exhaustion. You can however go back to IPv4 only, so clearly there is some IPv4 space, but perhaps not enough to cover every single customer in Ireland.
The other alternative is a proper dual stack deployment moves to VM Business and DS-Lite goes to residential. That would be acceptable for power users or enthusiasts, it would allow consistency of deployments across both types and if someone really hated that, they could just stay in IPv4 only mode or change provider if it's really not workable (if you have Openreach or an alt net available in your area of course). DS Lite likely works fine in most casual uses, but those that know or have more demanding needs it's just hassle waiting to happen.
