Dropping line and slow speed

[#1]

is that speed on the bare machine or when you are say P2P as my speed is currently unchanged  (or should I say good)
Date  Download Speed  Upload Speed 
Today 19:25 6344 kbps (793kB/s) 380 kbps (47.5kB/s) Share
Wednesday 19:19 5587 kbps (698kB/s) 268 kbps (33.5kB/s) Share
Tuesday 16:37 6193 kbps (774kB/s) 382 kbps (47.8kB/s) Share
Oct 14, 17:35 6927 kbps (866kB/s) 381 kbps (47.6kB/s) Share
Oct 9, 18:03 6608 kbps (826kB/s) 382 kbps (47.8kB/s) Share
Oct 5, 09:29 5485 kbps (686kB/s) 382 kbps (47.8kB/s) Share
Oct 3, 17:34 4827 kbps (603kB/s) 382 kbps (47.8kB/s) Share

[#2]

That is the machine basically doing very little. A bit of web browsing, but no more.
I do notice that the noise margin is fluctuating a fair bit and generally getting lower.

[#3]

It still isn't right.
The noise margin does drop during the evening but not usually that much.
As this is happening with the router connected to the master socket the only thing left is to use the fault system to get BT involved.
The thing which does concern me is your statement that this master socket has a decorative metal faceplate. This tells me that it is almost certainly not a regular BT socket but is a non authorised installation.
If this is the case I have no idea whether there will be a charge for putting in a proper socket.
I have assumed that the wires coming from outside can be traced back to the connection to the BT cable and not to a termination box somewhere

[#4]

We've only been in the house a three weeks. I can trace the wires to some bushes and then without ruining the garden, I can't get any further. But yes, it does sound as though I need to involve BT. Ho hum.
Thanks Jim - you are proving a mine of information.