[MovedGoalPosts]

Any cable on the street side of the master socket, including the connection to the master socket is the telco's responsibility. It can actually be against the terms of service for you to alter the telco's cable. You are only permitted to connect extensions and run those, from the extension connectors on the master socket.

Although phone line often has two or three pairs, often only a single pair is in use. But if you are making a repair in a length of wire that could be the cause of higher resistance or interference, reducing services. You'll only get that corrected by a replacement wire. But if you don't get a ringtone on your extension, and yet do on the master, that suggests you have connected something incorrectly, and that could explain the dial tone issues, and broadband speeds.

There will inevitably be a charge to call out BT. As your provider is Talk Talk, it should be arranged and co-ordinated by them.

If there is a call out, it would probably be charged as if it were a new connection (it's not Talk Talk Bt's fault the cable was damaged). If they are charging as if it's a new connection, because they are haveing to run a new wire from the street, then you should be able, within reason, to get the master socket positioned where you wish.