The telephone extension wiring here appears to be a bit odd.

One of the extensions, with the wire buried in plaster, died recently -
I suspect it got wet with the recent flooding, and we started getting
noise on the line. It's currently been disconnected from the master, and
the line is all nice and clear at the moment, phones connected elsewhere
happily ringing away.

I was going to put another wire in, which would be a simple enough
process. Except when I've pulled off the faceplate (genuine BT extension
plate, not the master socket type with the removable front), I've
discovered it's got the capacitor, resistor and surge protector of a
master socket.

I'm now wondering if I should :

a) Just wire it in with pins 2,3,4,5 as normal and not worry
b) Get a plain faceplate
c) Modify this one by disconnecting the various components leaving just
pins 2+5 connected.

Any thoughts?

(ADSL is filtered off at the master socket with a faceplate - can't be
doing with having individual filters for each phone and the potential
for any dodgy extension wiring to screw up the broadband)