Box changes can be done as a self-install, so you would be looking at a £20 delivery charge. I would pick up the phone & talk to Retentions (150 option 4 then 5), they are open 8 till 8 Mon to Fri, 8 till 6 on sat. As you don't have a TiVO yet, they may be able to re-bundle your services & get you a cheaper deal.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV+), Talk Unlim Telco, VIVID 100, Virgin PAYG Mobile