Thanks for the explanation.
I will monitor for a while to see what happens next as I am now connecting at less than the guaranteed minimum 😞
If you have any extension wiring, it might be worth leaving the hub connected to the test socket behind the removable faceplate to ensure your internal wiring isn't having an effect.
I will monitor for a few days and if necessary flag it up as a fault with Bt.
Bt have checked my line and say there are no problems but I've heard that before
New figures for today. Speed down even lower now and again , seems to be connected to a rise in noise margin !!
Now even further below the guaranteed minimum speed of 20