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 don't think I bothered asking them again!!
(Edit "them" = Virgin Media)
in my case, they did this without input from me.
I only found out because I could no longer access a swath of things I used to be able to.
not virgin media, but in the EU
[dead]
Sure they didn't just mean they'd change your static IPv4 address to a different one?