I'm coming back to make a note on this issue, I've already tagged @XRaySpeX on the EE community forum with the same info about the (eventual) fix to the issues I've had.
A couple of weeks ago Openreach did a new install near me and my download speed dropped by 15Mbps. I was getting 59/8 on average before. It went down to 44/6
I called EE and reported this, the checks came back to say I was within the minimum range but they agreed that a drop of 25% was not good so booked an Openreach visit.
He came on Thursday this week and did some checks, but couldn't figure out what was wrong. He changed pairs as there was some contention with the recent install, seems I was on the next pair to that. A bit of improvement was seen, but not back to where I was.
So he left as his day was up and came back Friday morning. Lots more testing, he checked each stage of the run from the exchange to my home, at the cab, at the pole, at a chamber DP on the way to the pole. All was fine up to the chamber. He could see 71Mbps there. So it came down to a 40 meter run between the chamber and the pole.
That's where he scratched his head a lot until he discovered that when the line was provisioned, only 2 years ago, they had an issue and had connected my line to an old underground cable that ran from 'my' pole to a more distant pole, with an overhead wire coming back in this direction. Yes, they had connected me to that loop, totally unnecessary.
Today the engineer disconnected the loop and put me on the nearest pole, as it should have been in the first place. A really good result, for him and me, as I now get 69/17 !!!
That's 10Mbps more download speed and double the upload speed. That is more like I should have got 2 years back.
Here's today's info from the hub
Data rate:17.08 Mbps / 68.91 Mbps
Maximum data rate:16.97 Mbps / 69.10 Mbps
Noise margin (up/down):6.0 / 6.0
Line attenuation (up/down):25.0 / 17.4
The Think Broadband speed test comes in at 64.2/15.6
EE Fibre Plus