Do you have a landline phone? Are you switching that to Virgin?
Whilst BT (OpenReach) cables are separate from Virgin Media cables there are (or were) circumstances where they might need to disconnect (but not really remove) each others wiring for telephone connections.
As you probably know, Virgin are moving landlines to the broadband connection, so the phone port is on the hub. If you have any extensions wired in, and want to continue using those, you’d need to sort out suitable wiring, bypassing the BT master socket.
Incidentally such incidents are seemingly common - when my daughter moved and wanted to take her Shell broadband with her, because it was cheap, Openreach found that a fibre provider had allegedly cut their cable into a whole block of flats in London. It would take months and planning permissions to resolve. She had little option but to go with the Fibre provider. She got faster speeds but had to pay double.
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I know a bit about Wi-Fi, Telecoms, and TV as I used to do it for a living but I'm not perfect so don't beat me up... If you make things you make mistakes!