You can do it, all wires should have been disconnected at the street cabinet, and there's no enduring right for VM to leave their wires and boxes on private property unless it's to deliver services to the property owner/tenant, or in cases where they cross private land and have a wayleave agreement (but that won't apply to the brown omnibox and the wires for a single private installation). There is a small possibility if you do this that VM would mark the property "unserviceable" meaning you'd not be able to connect if you wanted to join VM in the next few years they'd say no.
