ADSL - Slow speed now been stuck at around 28kbps ...

Question

We usually get up to 2.5MB ADSL speeds but at the moment we get around 28k which seems to be consistant and unbearable.    
Or configuration is as follows,
Hub v3 is plugged directly into the master socket.
Phone is on the extension with a filter on the line.
Taking a look in the event log in the BT Home Hub for the last connection we see,
18:21:08, 07 Apr.
(55036.570000) DSL noise margin: 5.90 dB upstream, 6.20 dB downstream
18:21:07, 07 Apr.
(55035.410000) DSL line rate: 911 Kbps upstream, 280 Kbps downstream
4. Board version:
BT Home Hub 3.0A
5. ADSL uptime:
2 days, 03:47:19
6. Bandwidth:
911 / 280
7. Data sent/received:
0.1 / 1.1
To try and remedy this we cycled through the following,
Re-started the hub - no change
Took out the BT Accelerator filter on the master socket, thinking it may be faulty - no change
Changed the filter for another one on the extension phone line thinking it may be faulty - no change
Plugged the Hub directly into the Test Socket - no signal
The broadband speedtest gave the following
"We haven't been able to complete the speed test at this time. This may be due to a problem with the speed tester, or your line may be running very slowly."
Any other Ideas welcome.
Thanks,

Answer 1

So I am performing the ultimate Broadband test - Plugging the HUB directly into the test socket with a filter connected between the socket and the HUB.
I reset the router to get a clean start.
The results are as follows,
ADSL Line Status
Connection Information
Line state:
Connected
Connection time:
0 days, 01:39:00
Downstream:
280.6 Kbps
Upstream:
847.8 Kbps
ADSL Settings
VPI/VCI:
0/38
Type:
PPPoA
Modulation:
G.992.3 Annex A
Latency type:
Interleaved
Noise margin (Down/Up):
12.1 dB / 7.2 dB
Line attenuation (Down/Up):
50.1 dB / 31.5 dB
Output power (Down/Up):
14.3 dBm / 12.6 dBm
FEC Events (Down/Up):
0 / 0
CRC Events (Down/Up):
2705 / 896
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
0 / 0
Loss of Power (Local/Remote):
0 / 0
HEC Events (Down/Up):
1895 / 2766
Error Seconds (Local/Remote):
12243 / 1092
From the logs
06:51:16, 11 Apr.
(37452.880000) DSL noise margin: 5.90 dB upstream, 7.90 dB downstream
06:51:15, 11 Apr.
(37451.490000) DSL line rate: 899 Kbps upstream, 280 Kbps downstream
Running the Broadband Speedtest produces the following,
“We haven't been able to complete the speed test at this time. This may be due to a problem with the speed tester, or your line may be running very slowly. “
We then ran the following -  http://speedtest.btwholesale.com/
And got,
Download Speed(Mpbs) 0.13
Upload Speed(Mpbs) 0.42
Ping Latency(ms) 0.00
At best we seem to get - Download Speed(Mpbs) 0.25
Connecting directly to the test socket has made no difference. The broadband continues to be abysmally slow.
I would ask BT to kindly reset our profile if indeed this could be done on the line to improve the speed, i will then recheck again?