Hmm . . . That's somewhat messy and old. A little worse than I thought it would be.
So we can see that the socket in the kitchen is not connected to any of the wiring and just covers the recessed back-box. Within that box is an old style, screw terminal block and a muddle of wiring. It confirms that the service feed is underground . . . as far as I can tell.
It appears that CW1308 cable, from a earlier era, probably two pair (blue/orange pair 1 & green/brown pair 2), has been run into the room and under the edge of the carpet to a socket in the vicinity of the current Openreach fitted NTE5C plus SSFP. A some time in the past, a botch joint to a short length of more recent CW1308 cable (probably three pair) was added. Something seems to have "occurred" in that corner of the room. I can't quite make out what but it appears that the new NTE5C plus SSFP is attached to some plate or board, upon which the old, replaced, socket had been mounted.
It might be best for you to look in your local press for a classified advertisement by an ex-telecom engineer and have that under the edge of the carpet wiring replaced with new, along with tidying up within the the back-box of the redundant socket in the kitchen.
Although it is something that I (or quite a few other members) could do, I would not like to try to tell you how to do it yourself.
[I see that a number of new posts have been made whilst I was typing a reply and valid points have been made. For completeness, I'll leave the above.]