If you can leave the box where it is & use a long HDMI cable I would do so.
The specialised triple screened coax VM use for internal connections is not commercially available. This cable has to prevent ingress of signals on DTT & DAB frequencies that VM re-uses for its own services, so the cable & connectors have to be "watertight", or they can not only disrupt your services, but track back down the cable & possibly affect your neighbours services. The other issue you could end up with is that your signal levels are adjusted for your current installation. Any change to the cable length or connectors usually has to be compensated by an adjustment in the street cabinet.
VM charge £99 for a non fault callout, so the long HDMI is by far the cheapest option.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV+), Talk Unlim Telco, VIVID 100, Virgin PAYG Mobile