Ok, this is how I see it has been wired. The incoming feed in the dining room (ex master) has been connected to the blue pair of the cable that goes to the normal NTE5 socket (not the MK3) and that is the master socket. The orange pair then feeds back the phone in the dining room. The other cable in the master socket then feeds the MK3 socket which is connected as a slave socket. I then don't understand where the second cable in the MK3 socket goes to and where its blue pair is terminated. The other confuisng thing is that there are only 3 crimps at the rear of the old master socket. The incoming wires should have been orange and white, it looks as though they have been extended by some blue and yellow jumper wire but only the yellow seems to be connected, I can't see where the solid blue wire is crimped to the incoming feed orange wire.
Ok, maybe the blue pair from the dining room go to the Mk3 socket first then, I couldn't see the blue pair in those photos only in the other socket. In which case the blue pair in the slave socket are probably superfluous. Still don't undestand why there are 2 cables in both of the sockets, is there another socket somewhere else? Can you get a clearer picture of the dining room wires. The incoming cable should have 4 wires White, Orange, Green and Black. The Green and black will be spare. Rather than connect the orange and white wires directly to the blue pair of the incoming cable it looks as though the engineer first connected a couple of piieces of scrap jumper wire to lengthen the wires. However there only appears to be 3 crimps, there should be 4 the one that seems to be missing is one connecting the incoming orange wire to the solid blue piece of scrap wire.
Which socket do you get dial tone on?
I can ring out from all four sockets. There are four crimps which you will hopefully see from the pics. Will the orange wires that sometimes pops out on the MK3 socket when taking off the faceplate cause an issue. How is best to reconnect it?