It’s absolutely true that Virgin Media can use Openreach assets ( like poles , ducts , joint boxes ) using the enforced PIA ( physical infrastructure access ) arrangements , the same as any other provider that wants to use this arrangement, but it’s a one way arrangement, VM can and do use Openreach, but Openreach cannot use VM ( same as City Fibre and Netomnia and many others they can use OR but OR cannot use them ) so if VM provided the Toby box , even if it links back to Openreach infrastructure, it’s still only usable by VM .
If your address can be served from a pole , then it’s odd that VM simply didn’t put their FTTP equipment on that pole ( they do overhead provision as well as underground using PIA ) but apparently they used UG for your address for reasons known only to themselves,.
Your property doesn’t seem to have been built in an era when ducted feeds from BT/Openreach we’re the normal method, so presumably your address was previously served from that pole , or had an armoured buried cable ( when the property had ‘BT’ copper pair service ) if it were an armoured cable and a pole was available then obviously the pole is used , if the pole was used for the copper pair service then there really isn’t an issue also using it for FTTP .
