ADSL mysteriously dropped from ~6Mbits/s to 300kbits/s

[#1]

ADSL mysteriously dropped from ~6Mbits/s to 300kbits/s download for past 5 days or so. iPlayer etc. is useless at that speed but we can scrape by with sluggish email. Upload speed is good at 600bkit/s.
My kit has stayed the same, but I went through the rigamarole of trying different filters, going into the master socket, waggling connectors. The router has always been very reliable and is not an obvious candidate for something breaking.
Went through the portentous threatogram screens ("you will be charged if there is a speck of dust on the filter etc etc.") to report the problem to PlusNet and haven't heard a thing in ~48 hours. Hence my coming here to see if there is more insight.
I can understand the reluctance to involve BT OpenReach as they seem somewhat to be a law unto themselves as regards service provision and charging with no effective policing of their monopoly of ADSL.

[#2]

Hi DKP,
Your profile is all currently set correctly on our side, our faults team have just completed testing and your ticket will be updated very shortly.
If you need any help with this please let me know.

[#3]

Can you post the DSL stats from your Modem/router and the full results from a BT Speedtest (Diagnostic)?

[#4]

Thanks. I'm fairly confident that PN themselves will do their best, but I suspect that it will need BT OpenReach to go and do something. A friend had a lengthy broadband outage and it needed an engineer to go and "waggle the board" in the exchange. Trouble is that PlusNet have no real control at all over the standard of the equipment and wires that come to my door. (I rather take exception to the protection racket screens threatening unspecified charges that you have to go through to report a fault and that puts a rather unsavoury edge on trying to get things fixed when I am already wasting a lot of my time on the issue in good faith.)

[#5]

@Anotherone. Thanks, Yes, I'll do the master socket + wired ethernet  to router to get the stats from the router and BT speed test. At the end of a long day with an excitable toddler, it will make a change I suppose. Feels like living in a 3rd world country where the electric or water goes off with no warning and getting it fixed requires 58 forms in triplicate.

[#6]

No need to change to Master socket, just stats as they are will do.

[#7]

FIXED!
Or at least as good as before when it was functional for our low-tech household purposes.
Date Download Speed Upload Speed
Today 17:49 4842 kbps (605kB/s) 560 kbps (70kB/s)
Would be good if one could log on to PlusNet and hit a big red RESET button for the BT end of the link when it goes wrong!
Would save PN the hassle too.

[#8]

If you post up the full modem/router stats some time when convenient - Sync(Connect/bandwidth) speeds, SNRM (Noise margins) and Attenuation, Errors if available, then we can say whether your setup is performing as well as might be expected.