speed issues after connection finally sorted!

[#1]

I have been having terrible connection issues the past couple of weeks with constant disconnections & erratic syncing.
Yesterday I finally managed to sort it out by replacing the master socket faceplate with a new filtered faceplate & now
the connection is constant with no disconnects 
The router (dlink dsl2640r) is synced at:
Downstream Line Rate : 16611 kbps
Upstream Line Rate : 443 kbps
But I am getting really slow speeds of:
Today 08:28 474 kbps (59.3kB/s) 372 kbps (46.5kB/s) Share
Today 08:22 470 kbps (58.8kB/s) 373 kbps (46.6kB/s) Share
Could this be due to BT restricting the speed because of the constant disconnection issues?
If so, how can I get them to unrestricted it?!
Any help appreciated 

[#2]

If you do a BT speedtest (not the Beta version) you will probably find that the all-important IP profile has dropped to about 500 Kbps, for the reasons you suggest.
It should correct itself in a few days if the connection stays solid, with the Plusnet IP profile following suit soon after.
(My experience of this is that the BT profile either improves within a couple of hours or takes a couple of days.) 

[#3]

Quote from: harwin

Could this be due to BT restricting the speed because of the constant disconnection issues?

Yes, that's very likely

Quote from: harwin

If so, how can I get them to unrestricted it?!

BT always restricts your speed, the best you can hope for is that it is restricted to something nearer your current sync rate.  Plusnet also applies a restriction based on the BT speed restriction but with a delay in updating.  Your current restriction may be lifted automatically after a day or three of waiting or it may need a nudge.  What SNR ("noise margin") does your router report?  What is your IP Profile if you run the test at http://speedtester.bt.com/ ?

[#4]

What some fail to understand on all these boards is that data integrity is regarded as vital.
The BT system is designed such that once disconnections or other instabilities from noise are detected then the system will instantly reduce the speed accordingly.
The system will then monitor the line and only if it remains stable over a period will it gradually increase the speed.
Hence the complaints that while the system drops the speed suddenly it is slow to raise it.
The exchange DSLAM has no way of knowing whether your line's instability was a one off event - or is going to happen ever day/week/whatever: so its cautious.
In general if the line improves by a little bit the BT system will take many days to react - as it thinks this improvement may not last.  however if the improvement in sync speed is larger then the exchange equipement will raise the speed at a faster rate - at it realises that most likely a fault has been cleared.
This absolute priority of data integrity may seem rather overblown or uncecessary.....that is until you consider that people actually use the internet for ciritically important transactions - I'm talking interent banking & purchasing here.  That the correct figure arrives at the bank from your computer is actually rather important.
The origins of data transmission protocols and data stream error checking are based on rocket telemetry systems in the 1960's

[#5]

Trust RAMBo. He was well trained!

[#6]

Thanks guys, I'm currently waiting for a painfully slow java update to download before I can use the BT speedtest. I'll have to put my faith in rambo!
The downstream SNR was 6 last night and is currently 3.6 with 22db attenuation. Whilst looking at the router stats I've just noticed an obscene
amount of packet errors on the wireless receiving side:
bytes: 39544730 pkts: 234131 errors: 1436886 drops: 1436886
Could this be affecting speed too?

[#7]

OK done the BT speed test.
The first two tests confirmed the speeds I currently have although the profile was 14654Kbps.
When I done the third test (with BT username on router) I got these results:
 
FAQ
Results Image not loaded
This Last Test comprises of two tests
1. Best Effort Test: -provides background information.
Download  Speed
12957 Kbps

0 Kbps 21000 Kbps
Max Achievable Speed
Download speedachieved during the test was - 12957 Kbps
For your connection, the acceptable range of speeds is 4000-21000 Kbps.
Additional Information:
Your DSL Connection Rate :16610 Kbps(DOWN-STREAM), 443 Kbps(UP-STREAM)
IP Profile for your line is - 14654 Kbps
2. Upstream Test: -provides background information.
Upload Speed
349 Kbps

0 Kbps 443 Kbps
Max Achievable Speed
>Upload speed achieved during the test was - 349 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 443 Kbps

Your service was found to be performing poorly.
Please raise a fault with your service provider, stating that the BT Performance Tester tool indicates poor service throughput performance after the second test.
Please visit FAQ section if you are unable To understand the test results.
Hmmm, much better speeds through BT username then, should I contact plusnet with these results?