I sense a spot of misunderstanding. Please let me clarify.
Right from the earliest days to the present, there has only ever been two wires per telephone line. One hundred years ago your telephone line would have had a pair of wires (hence the usage of the word "pair" in a telephony environment) known as the A-wire and the B-wire. Today, your telephone line still has a pair of wires, the A-wire and the B-wire. (For completeness, the A-wire will be carrying about -1 V with respect to a good earth and the B-wire will be about -50 V with respect to earth.)
As long as any extension wiring, connected after the
NTE5/A, does not use more than two wires (connected to terminals 2 and 5, respectively, on the removable faceplate) then there will be nothing else (wiring wise) to do to ensure that your broadband service is optimised. Do you actually have any extension wiring connected?
As for your question "
The cable runs from the roof (overhead cables) can I get the wire replaced?", the simple answer is yes. However you will have to agree to pay the full commercial value of the items fitted plus the time related charges for an
Openreach engineer's time. (If you have the money and are prepared to pay, the
BT Group will do almost anything you want -- within reason!
)
In return, I have to ask the obvious question: Why would you like to have that cable replaced?