Connection drops on a daily basis / Varying (low) ...

Question

People probably know the drill by now, everything is fine then suddenly they go through a period where they receive barely a 10th of their paid connection speed, with their connection dropping completely at least once per day.
This all started happening when BT somehow increased our connection speed from 8Mbps to 21Mbps and also increased our upload from about 250kbps to 1Mbps which happened a couple months ago now. This was great! Everything was working fine, no drops in the connection or speed and it seemed like they had given us a nice boost for free.
That is, until things started going wrong about a month later when our connection would frequently drop, the connection speed would often fall to below 1Mbps and this is still happening.
With regards to solving this problem myself, I don't see how anything could be interfering with the setup I currently have, as nothing has changed within the house itself. Before I ring up an Indian/ Chinese/ Scottish/ Martian call center, I'd like to try and get some feedback from the users on this forum.
I'm going to buy some new ADSL filters just to see if the ones I'm currently using are packing up (they're cheap so that is no problem if nothing changes).
I have run quite a few speedtests using the recommended btspeedtester and have had varying results, all of which barely, if at all, meeting the acceptable range of speed for my line. Here is my most recent test:
 Download speedachieved during the test was - 4563 Kbps
 For your connection, the acceptable range of speeds is 4000-21000 Kbps.
 IP Profile for your line is - 11000 Kbps
Some additional info on my connection:
ADSL line status
Connection time
0 days, 00:46:06
Downstream
12,651 Kbps
Upstream
1,260 Kbps
ADSL Settings
VPI/VCI
0/38
Type
PPPoA
Modulation
G.992.5 Annex A
Latency type
Interleaved
Noise margin (Down/Up)
6.8 dB / 6.5 dB
Line attenuation (Down/Up)
18.3 dB / 8.9 dB
Output power (Down/Up)
20.2 dBm / 1.9 dBm
Loss of Framing (Local/Remote)
0 / 0
Loss of Signal (Local/Remote)
0 / 0
Loss of Power (Local/Remote)
0 / 0
FEC Errors (Down/Up)
2101 / 817
CRC Errors (Down/Up)
33376 / 1808
HEC Errors (Down/Up)
262820 / 0
Error Seconds (Local/Remote)
2101 / 771

Answer 1

Thanks again for the reply.
I connected to the test socket and saw a difference straight away when my internet reconnected. I ran another btspeedtest and here are the results:
 Download speedachieved during the test was - 8610 Kbps
 For your connection, the acceptable range of speeds is 4000-21000 Kbps.
 IP Profile for your line is - 11000 Kbps
ADSL line status
Connection Information
Connection time
0 days, 00:11:22
Downstream
13,838 Kbps
Upstream
1,272 Kbps
ADSL Settings
VPI/VCI
0/38
Type
PPPoA
Modulation
G.992.5 Annex A
Latency type
Interleaved
Noise margin (Down/Up)
6.3 dB / 6.3 dB
Line attenuation (Down/Up)
18.2 dB / 8.9 dB
Output power (Down/Up)
21.5 dBm / 1.9 dBm
Loss of Framing (Local/Remote)
0 / 0
Loss of Signal (Local/Remote)
0 / 0
Loss of Power (Local/Remote)
0 / 0
FEC Errors (Down/Up)
676 / 0
CRC Errors (Down/Up)
5613 / 160
HEC Errors (Down/Up)
60095 / 0
Error Seconds (Local/Remote)
676 / 100
I don't suppose it's possible to simply leave things as they are connected to the test socket?