You need to find out where the other end of one of the cables in the bedroom terminates. I suspect the wiring goes from an unknown point to the bedroom where it is teed to the cable going to the living room corner which is in turn teed to the cable going to the living room multimedia panel.
I have updated the file with the link...
The last two pages show how I can only assume the phone sockets might be wired.
There are 2 green cables in parallel for:
There is only a single green cable for:
I have know idea where one of the other green cables will go (labeled '???'). It must either go from:
There is another socket in the cupboard under the stairs, but I believe this is for an alarm installation. See last page of updated document (via the dropbox link).
Yep, as I described in message 3. You need to discover where the other end of the ??? cable is. Hopefully its somewhere in the under stairs cupboard.
Its not coiled up lurking behind any of the Openreach boxes is it?
I think you may need to speak to the developer, one of your diagrams, on page 9 or 10 will be correct , but which one ?
The developer or whoever he employed to install this wiring should be able to locate the end of that mystery cable and it would then need to be terminated on a line jack socket , then the FVA (fibre voice access) cable (with the regular phone plug) would be inserted into the (new) line jack , and that should bring the three existing sockets into service...it looks like the developer has messed up and not provided all the sockets required...I doubt OR would get involved in this
You could buy an extension kit, but that would be a shame to have surface wiring when everthing else is hidden, or you could buy a double line jack unit , plug the FVA lead into one side, buy a set of DECT phones, leave the base unit under the stairs with the rest of the kit, plugged into the other side of the double socket , and position the handsets where you want them and abandon the pre fitted phone sockets, you may need another mains outlet if you go down this route