Have a look inside the socket in the lounge as well as the one in the hall. Are you sure the one in the lounge was only fitted after the one in the hall?
I would like to know where the phone line reaches the house and how it gets from there to the master. (Which I'm suggesting may not be in the hall).
You've got little chance of altering anything significantly before the FTTC goes live, bar one important thing. You can
gently remove the ring wire at the master when you find it and curl it out of the way. Don't cut it. The phone and broadband wires are on terminals 2 and 5. The bell wire is on terminal 3. The important end of it to remove is at the master. Far less important at non-masters but some people like to do those as well.
Remember, it is going to work just like now. Just probably degraded, and a possibility of instability. You are right to want to clean it up, but don't panic

. Given the high estimates I doubt if the speed will be below 40Mbps connection anyway, but instability could clobber it after a few days.
An
explanation of the bell wire, with a picture showing the inside of the NTE5A and faceplate. As you can see, the faceplate is only part of the front of the socket, but your picture shows a non-split front. There is no filtered faceplate to fit your photo'ed socket. The speed difference quoted there is for ADSL/ADSL2+. For FTTC it is far greater.
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