I find this whole thing a bit confusing. Virgin Media service is usually provided by them through their own network, which they inherited as the successor to various cable TV companies (Nynex, Mercury Comms, Cable and Wireless) and is completely separate from the phone network. Their cables are installed in the street but individual homes are typically only connected up when the occupier actually signs up for their services (phone, TV, broadband but mainly broadband these days).
In my experience (n=3, in various areas of the country), Virgin will install the cables from the street into homes themselves, and will do this in the easiest, most slapdash way possible - 'underground' in the shallowest trench under a flowerbed, or clipped along a wall or fence. The actually entry into the house will be through a hole drilled in the wall. I've never known them to use any kind of cable duct or 'pipe'.
To complicate things Virgin Media will also provide "conventional" broadband over the public telephone network managed by Openreach (formerly the BT network). Depending on the area this may be in copper or 'full fibre' in some areas (i.e., fibre to the actual home). In this case Virgin, like any normal broadband provider, will work on the basis of the infrastructure being in place. It usually is, because most homes have a phone line (or used to have one). If there isn't a phone line, or you want full fibre service and the line for this isn't in place, then Openreach have to sort it. You cannot mess with the Openreach line as a householder, and no contractor will do the work for you, it has to be done by Openreach or their own subcontractor.
The OP doesn't quite fit with the first scenario because I'd expect Virgin to sort their own cable out in that situation. But the second seems unlikely too, as most homes already have a phone and broadband service through Openreach managed infrastructure, and the Virgin installer would not (or at least, should not) advise anyone to get their own person in to sort the issue out.
@womble2023 - it would probably help people to give sensible advice if you could clarify the situation as you understand it. Does your house currently have phone and/or broadband? And are you living in a Virgin Media cabled area, where you're probably trying to get their own cable broadband service, or a non-cabled area, where you're trying to get 'normal' broadband or 'full fibre' broadband from them over Openreach assets?