New contract - 'old style' 1980 fixed master socke...

Question

Hi
LJ2/ socket!!
I couldn't believe my eyes, when I came home from work one day!
An ancient socket fixed behind a chest of drawers [when I requested to put on the wall above it]
But this guy from BT Openreach convinced my girlfriend that it's better to have it behind heavy piece of furniture...
just in case someone wants to look at it - me! [http://en.wikipedia.org/wiki/File:LJ_Front.jpg]
So if I want I-Plate I will have to pay again £120.
Thank you mister openreach!
Another reason I came here today;
Two years on the new contract and my average download speed only twice exceeded 1Mbps. [i know because I monitor the network]
The last time it was in November and I enjoyed +4Mbps for couple of days [so this is the true capacity of my line]
But since I remember my average download speed was solid 100-110KB/s and when I look at monitor graph it's a straight line, never up and down.
Does it mean that my line is capped?
I didn't complain to BT before - mainly because I have only bad experiences with their customer service and it cost me dearly when I have to call them so - I learn to live with that...
But now my girlfriend use it more and more and she needs fast internet for her study.
So here I am:
Router statistics, last night: 
ADSL line status
Connection information
Line state    Connected
Connection time    4 days, 8:41:39
Downstream    1,107 Kbps
Upstream    800 Kbps
ADSL settings
VPI/VCI    0/38
Type    PPPoA
Modulation    ITU-T G.992.5
Latency type    Interleaved
Noise margin (Down/Up)    7.6 dB / 8.3 dB
Line attenuation (Down/Up)    52.0 dB / 28.5 dB
Output power (Down/Up)    15.3 dBm / 12.1 dBm
Loss of Framing (Local)    0
Loss of Signal (Local)    0
Loss of Power (Local)    0
FEC Errors (Down/Up)    0 / 120
CRC Errors (Down/Up)    3966 / N/A
HEC Errors (Down/Up)    N/A / 187
Error Seconds (Local)    2967 
Broadband Performance Tester:
1. Best Effort Test: -provides background information.
    Download  Speed
    869 Kbps
0 Kbps    1000 Kbps
Max Achievable Speed
 Download speedachieved during the test was - 869 Kbps
 For your connection, the acceptable range of speeds is 400-1000 Kbps.
 Additional Information:
 Your DSL Connection Rate :1104 Kbps(DOWN-STREAM), 800 Kbps(UP-STREAM)
 IP Profile for your line is - 973 Kbps
2. Upstream Test: -provides background information.
    Upload Speed
    664 Kbps
0 Kbps    800 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 664 Kbps
 Additional Information:
 Upstream Rate IP profile on your line is - 800 Kbps
I do hope I find someone who can help me.

Answer 1

Thank you for your reply, imjolly.
Yes, this is the master socket and the only one I have access to.
There is another guy [we live in shared house] he has bt vision; he says he never go below 4Mbps
I would use your advice - but I'm not sure it is legal to fiddle with BT property.
Apparently bellwire is not the cause of my trouble since I know that my line can carry +4Mbps easily.
I want BT representative to answer few questions:
1. How was it possible in 2009 I have new line fitted with 1980 socket?
Who is responsible and how it will be fixed?
2.  Is my line capped?
3. Is my line faulty? When can you check and repair it?
My recent statistics: 
ps. I fixed formatting issue in my first message.
I was a complete mess, no wonder only one reply.