Thanks for your help. My only concern is when I saw the JDSU the attainable rate vs max attainable was 99% on the upload and I think the max was 8100ish. And also the way he installed it, the VDSL faceplate is not on the master socket, is that ok?
When I had FTTC installed, the engineer hard wired my existing extension cable from the original master socket, (upstairs), bypassing everything in the original master socket, to the new master socket position (downstairs).
He then wired from the new master socket's faceplate (using a spare pair of wires in my cable) back upstairs, making the original master socket effectively an extension, also changing its faceplate from its original separate ADSL & telephone sockets to a single telephone socket.
This "back-wiring" raised a few eyebrows, but it all worked perfectly (until my connection "issues" started - a month later).
I believe my issues are completely unrelated to how the installing engineer wired up my connection.
I presume your installing engineer has done something very similar?
You could check by removing the faceplate at what was the master socket to see if what was your extension cable is now connected directly to the incoming drop wire.