I once asked them if we could enable IPv6 on a 1Gb DIA circuit, and the response I got back was that "we can convert the circuit to IPv6, but you'll need to give up your IPv4."
I’ve seen this commonly from them with residential service. They mostly give you a private v4 address behind CGNAT in addition to IPv6. If you want a public v4 they put you on their old network which has no v6.
I don't think I bothered asking them again!!
(Edit "them" = Virgin Media)