Router Data

[#1]

Can we just go back to first base for a moment.
As I understand it you have a single socket in the flat to which your phone and modem are connected. If you don't have any other extensions in your property then whether there is a modern master socket or not is irrelevant as the problems you are seeing are being caused before your socket.
It is possible that when the broken cable was repaired some of the damage was not fixed as it could easily have been damaged away from the actual break if it was done by snapping rather than cutting the cable.
As far as I am aware the only reason BT would suggest getting another electrician to repair the damage is if it wasn't their cable. This would only be the case if the incoming BT lines to the property terminate away from the individual flats and all the subsequent cabling is the responsibility of the landlord.
You can appreciate if that is the case then the problem becomes much more difficult and expensive to solve.
A little investigation may be called for to see if my supposition is correct. If it is then getting an NTE5 master socket fitted in your flat would almost certainly be a waste of money although you wouldn't need to have BT do it as it would not be their property.

[#2]

Note illegal is a very sick bird

[#3]

I would like to thank everybody for the input to this post. What I did was set up a wireless connection with the router plugged directly into the existing socket and my line speed has jumped dramatically,

Line Mode G.DMT  Line State Show Time 
Latency Type Interleave  Line Up Time 00:02:25:30 
Line Coding Trellis On  Line Up Count 1 
 
Statistics Downstream Upstream 
Line Rate 5792 Kbps 448 Kbps 
Noise Margin 14.9 dB 22.0 dB 
Line Attenuation 37.0 dB 20.0 dB 
Output Power 19.8 dBm 11.8 dBm 
K (number of bytes in DMT frame) 182 15 
R (number of check bytes in RS code word) 14 4 
S (RS code word size in DMT frame) 1 4 
D (interleaver depth) 32 8 
Super Frames 513542  513540 
Super Frame Errors 6  0 
RS Words 34920880  8730180 
RS Correctable Errors 1176  0 
RS Uncorrectable Errors 107  0 
HEC Errors 5  0 
OCD Errors 0  0 
LCD Errors 0  0 
ES Errors 0  0 
so now it's just a matter of wait and see what happens, thanks again, Jack