Tried all the steps suggested and it appears Line ...

Question

Since we had a power cut on September the 13th to the 14th our download has speed has been stuck on a far lower profile than previously which was just sub 20 meg the upload speed has slowly retrained its way back up to what we had previously. I have checked all wiring I have checked for interfrence using a AM radio and also ensuring as many devices in the house are off. I have checked with neighbours who appear to be getting the service they had previously.
 I have purchased a couple of new Belkin Micro filters when the issue first occured and both give the same speed 6652 an older standby filter the download speed dropped to 5 something and then went straight back up to six with one of the new microfilters.
When I attempt a speedtester BT it says my speed profile is 5.87 mps and has constantly said over the time since september 14th or when ever i first tested most likely the the 15th i think.
 The Broadband has been up as far as I am aware for more than 3 days and probably nearer 10 days with no reconnection made since a very short power cut occuring on the 17th.
 I have also tried different routers which are known to work ok including a BT Home HUB and a Billion 7700n
 I have changed and tested with different cables.
 I have put ferrite cores on the power supply cables and even tried different power supplies (I can obtain from my workplace for testing purpose
 I have checked with the Bt silent line test 17070 option 2 on numerous occasions
I have purchased a new phone to ensure the line was not affected by a landline but for the last ten days we have left unconnected. There are no extensions.
 The Broadband is connected to the feed bt supplied when the house was bulit 20 or so years ago.
 The router is less than 15 cm's from the router and uses a short quality cable and as mentioned before other quality cables have been tested. I have also ensured by flexing the cables no difference was noticed.
 So please advise please BT thanking you in advance details from Billion 7700n Router
The device has been reset and the settings reinputted post power cut to ensure no corrruption of the flash memory.
Mode:
ADSL_2plus
Traffic Type:
ATM
Status:
Up
Link Power State:
L0
Downstream
Upstream
Line Coding(Trellis):
On
On
SNR Margin (0.1 dB):
196
108
Attenuation (0.1 dB):
165
78
Output Power (0.1 dBm):
0
119
Attainable Rate (Kbps):
22516
1028
Path 0
Path 1
Downstream
Upstream
Downstream
Upstream
Rate (Kbps):
6652
1028
0
0
MSGc (# of bytes in overhead channel message):
94
10
0
0
B (# of bytes in Mux Data Frame):
14
23
0
0
M (# of Mux Data Frames in FEC Data Frame):
1
8
0
0
T (Mux Data Frames over sync bytes):
9
6
0
0
R (# of check bytes in FEC Data Frame):
16
6
0
0
S (ratio of FEC over PMD Data Frame length):
0.716
5.9325
0.0
0.0
L (# of bits in PMD Data Frame):
3463
267
0
0
D (interleaver depth):
416
4
0
0
Delay (msec):
7.44
5.93
0.0
0.0
INP (DMT symbol):
7.68
0.35
0.0
0.0
Super Frames:
51250288
46086640
0
0
Super Frame Errors:
562
76
0
0
RS Words:
3531973953
1701220
0
0
RS Correctable Errors:
127
709
0
0
RS Uncorrectable Errors:
0
0
0
0
HEC Errors:
859
62
0
0
OCD Errors:
0
0
0
0
LCD Errors:
0
0
0
0
Total Cells:
848137411
1456617343
0
0
Data Cells:
306154883
23579826
0
0
Bit Errors:
0
6559
0
0
Total ES:
29
65
Total SES:
12
0
Total UAS:
84
84
Speedtester results same time the above was taken
1. Best Effort Test: -provides background information.
Download Speed
5.53 Mbps
0 Mbps
7.15 Mbps Max Achievable Speed
Download speed achieved during the test was - 5.53 Mbps For your connection, the acceptable range of speeds is 2 Mbps-7.15 Mbps. IP Profile for your line is - 5.87 Mbps
2. Upstream Test: -provides background information.
Upload Speed
0.9 Mbps
0 Mbps
0.83 Mbps Max Achievable Speed
Upload speed achieved during the test was - 0.9Mbps Additional Information: Upstream Rate IP profile on your line is - 0.83 Mbps

Answer 1

Thank you Roger for taking the time to reply
"The router is less than 15 cm's from the router " what does this mean?
Router to the Telephone socket sorry typing faster than I think (Which is not very fast )
"I have also tried different routers which are known to work ok including a BT Home HUB and a Billion 7700n
 I have changed and tested with different cables.
 I have put ferrite cores on the power supply cables and even tried different power supplies (I can obtain from my workplace for testing purpose"   Clearly, quite a few line interventions?
That is true but nothing has been touched or altered in the last ten plus days I think its 12 days since I have touched anything and left it to its own devices to see if it retrained it self I think is the phrase.
 "I have checked with the Bt silent line test 17070 option 2 on numerous occasions" .... and the result?
A very very clean line it seemed but saying that not much of the Broadband signal occurs in our hearing range so I am presuming it helps but not much. 
The device has been reset and the settings reinputted."  .... which device?
Whoops the billion device again this was done more than ten days ago.
The line is running excessive interleave and INP is well up, thus the lack of throughput.
There's clearly a noise issue, allbeit some of it is down to excessive line resets.
Although the original phone socket will probably work well enough, and with no extensions to contend with, that
close to the exchange, you would benefit from a proper NTE socket (network terminal equipment).
And even better an SSFP (service specific faceplate) gives phone and broadband segregation.
 It is an old socket but had worked perfectly with a very very good Speed up 1mb and down 19mb especalliy since the Billion router was bought in the summer of 2011 with a big improvment over the BT hub in down and up speed. But I can imagine possibly speed is at the cost of stabilty.
I guess i will investigate a new socket but as BT I am sure will want money out of me I will see if its not another issue first.
So far as the billion router is concerned, I'd be inclined to stick with a hub, there are far better routers than the billion and at the approximate same price.
(personally I'd take it outside and tee it up). 
Well will have a look at swapping Hubs but seems odd the profile hardly changed apart from when I used a older filter.