You wouldn't have upgraded from a V6 to TiVo. You would have had an older V box. These are all disabled and decommissioned.
Virgin Media contribute to the WEEE DTS scheme to cover kit that they don't ask for back
https://www.gov.uk/electricalwaste-p...akeback-scheme
At no stage is legal ownership of the rented kit transferred to customers for resale. This means any rented Virgin Media kit that is on eBay is still illegal.