Thanks for everyone's help on this. I have not paid much attention to the technical solution given that I know I have a problem with my line. Unfortunately, I cannot locate my BT master socket.
The socket to which my phone and router are connected is in my living room. I always presumed this to be the master socket, but I know for a fact this is not the master socket and is actually an extension. Tracking the wire that comes out of this socket, I follow it to a small box which is actually covered by the side of my sofa. This looks like a master socket to me... a very old one but I'm 99.9% sure this is the master socket to which my landline is actually connected and from which I receive internet. The wire that comes out of my telephone socket and goes to this master socket wraps around a door frame and goes under my laminate floor and then resurfaces under some beading and eventually into the master socket. This wire is a bloody mess! It is broken in several places and has been manually repaired and sellotaped back together! I am now also 99.9% sure that herein lies the reason for such deficient broadband. It is my old wiring and infrastructure. I am certain of it. I attach a photo which has been entitled 'Sofa' , but just in case the title doesn't appear on the upload, it is the picture which has a square like ratio.
I am 99.9% sure I am correct. Which means I am 0.01% unsure I am correct. This ambiguity comes from the fact that I have another master socket in the house. This master socket is in a location which makes a lot of sense... right in the hallway of the house... right near the front door. Somewhere BT came and put a line over 60 years ago (I'm presuming) and just dumped it in the property. This seems logical... more logical than on a side wall (which happens to now be covered by a sofa that extends from the wall to the door frame of this room), which is actually somewhere in the middle of the property. So far making sense right? This other socket must be the master right? When I go outside my house and look at the BT pole which connects the houses on my row to ... well British Telecommunications... (and I know it is BT's pole from a BT engineer visit to my house a million years ago), there is only one wire going from that pole to my house. That wire can be clearly tracked to the side of my house... it goes into some ventilation griddle which is extremely close to the opposite side of this other master socket in my hallway. I have called this socket 'boiler' (because it is near my boiler), but again if the title doesn't appear in the attachment, the ratio of this picture is more rectangular/oblong. Clearly a BT master socket right? And logically this is THE master socket right?
The reason I'm still more sold on the idea that the sofa socket is where I am getting my landline and internet from is because the wiring for the boiler socket cannot be traced to the telephone socket. You can make some guesses as to where it is going, but it really is not easy to trace it (without ripping my my floorboards and going through the door frame).
So anyway... all this means I really need to fix this problem before I can progress to the next stage of throttling internet speeds.
I've already called Plusnet who have said they think there is a problem with the line (after having run some diagnostic tests whilst calling the callcentre) and they are sending an engineer to fix it. But they also said if there is any problem on my side of the property, I am liable for the charges.
I have a fear that the problem is twofold - 1) the thing they said they detected on the line and they will now look into - and 2) the [-Censored-] wiring in my own house.
Is there any advice you can give me on fixing the wiring? What do I do with this ancient old socket? I can probably procure a new wire and wrap it around the doorframe but as to connecting it back to the Master and the regular socket... I'm at a loss. This is all assuming that I am right... that my master socket is actually the sofa one. Should I just wait for the engineer to do his business? Is it better to let him/her do their business and pay them rather than cowboy the job myself? What do you recommend? I would just hate to cough up £200 for a job that can be done with 0 technical knowledge.
Regarding the actual reason for this post... you know... throttling the internet on certain devices... I was thinking.... is it not possible to set up a virtual router? I.e. the actual router's job is just to route data to a virtual router. Then on the virtual router, I can mess around with functional settings which would be limitless? Or is my imagination running too wild as a result of all the talking I've done about BT Master sockets?!
Thank you @bill888 for all your help and support on this issue too... your reading materials and guidance are very helpful.
