Virgin Media is a cable operator, all your services are fed over the incoming cables. The roof antenna will be providing a Freeview feed, so it depends whether you have any requirement for that.
Hi, I have a wifi 6 router, virgin volt 360. Before I take my roof antenna down, can someone confirm that all my TV signals come through the fibre and not the roof antenna?
I would keep your antenna as a backup. Something as simple as a cabinet amplifier failure could result in services being down until the next day while a new amp is sourced & calibrated.