You can't use a wireless extender as the phone line is monitored, the extender might be able to provide 50v at the panel, but what if the actual telephone line goes down??, it won't be monitored.
Virgin and bt will always put the master socket where it is easiest for them. There all tw@ts, just like sky and all the others.
At first, i agreed with norman, but then also not sure why they want to puta new 'box' in and charge 1000. They could run a new cable to the master socket and bill you for that. Might be a case of having your pants down.
Telecoms chap is probably the way to go, although i'd of fooked off the virgin engineer andtold them were to shove it.