Be warned, as its not a fault callout, the standard callout charge applies (£99). This includes the alteration, & a check that the signal levels are balanced. DIY jobs on VM's network coax are a non-starter. The cable they use is specially made, & any non-standard alterations could potentialy cause problems affecting the whole street.
Considering the above, would a long HDMI cable be a better option? It would certainly be cheaper.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV+), Talk Unlim Telco, VIVID 100, Virgin PAYG Mobile