Broadband speed absolutely dire

[#1]

The 5 day period was when there was no phone connection - stolen cables near exchange

[#2]

Jim,
Thanks, clearly this heavy cold is sapping my brain cells! 
Kevin

[#3]

@ Kevin - These should be the times at which the profiles were physically altered on our side (that's me working on the premise of this being how we refer to them internally) however I'll double check this with someone in the know just to make sure.
Update
Date/Time stamp is confirmed as the changes on our side

[#4]

Adam,
...an aside to the main issue, but these date / times do not correlate to PPP drops on the radius plot, even if presuming one set of times is GMT and the other is BST.
Is this specific evidence useful to those investigating the failure to drop PPP when applying profile updates?  Or is that done sometime after the profile has been applied and thus attempting to find correlation is fruitless?
Kevin

[#5]

Hello again, I've set up the router stats on my Windows PC I only hope that I've captured useful and relevant stuff. I'm certain that you will advise me if not. I have run the stats for the previous 3 days for around 1 hour each time. These router stats are all taken from the extension socket in the office of my bungalow which is where everything normally lives. If these stats are not helpful I will move the router to the main BT socket at the front of the bungalow which is in fact my kitchen and try from there. Please note that the stats taken today show a dramatic drop off, followed by another drop off. That was me checking the connections in the main socket and then retrying to confirm that I'd caused it, I also checked the extension sockets with no loose or disconnected wires found I've also changed the microfilters on all the sockets. I have read through your updates I'm afraid they mean nothing to me. I will now attempt to attach the router stats.

[#6]

Hi Lindap,
This is excellent - exactly what we are looking for, but the news is not good, which I will explain directly.
Note that some of the recent updates have been side matters between myself and PlusNet's CRT as the evidence they have produced in respect of your problem illuminates issues being discussed elsewhere, the characteristics of which have had a bearing on your perception of your problems.  To clarify - you've complained twice that your speeds have slumped and after a bit of fiddling on PlusNet's side all has appeared to be OK.
The fiddling relates to PlusNet updating the data speed profile in response to changes notified by BTOR.  What has not been explored is why the BT reported speeds have being changing so much.  The graphs you have provided show some potential causes - REIN (aka electrical interference).  Intermittent noise can cause the link to be lost and reconnections then result in very low speeds...
When looking at a SNRM plot, when the line drops (as at 18:40) it indicates the presence (start) of REIN, when the line rises, it indicates the removal of REIN.
We need to run these graphs 24x7 please and note when the lines shift and think about what is being switched on / off / brought out of standby when the line jumps.
I would prefer if you could connect the router to the TEST socket behind the lower faceplate on the master socket - note this will disconnect all the extensions - and thereby eliminate any possible contribution from the internal wires.  Whilst you have the face plate off (ideally look at all of them) can you please identify how the sockets / pins are wired - numbers and wire colours will tell a lot about the wiring standards.
...We have some way to go, but you have made excellent progress!
Kevin