Download speed at 125k or below for the last 2 wee...

Question

We've been having a fair amount of grief over the last couple of weeks. We usually have a download speed of 2mb with some periods where it drops down to near-dial-up speeds. If these don't clear automatically I will force a disconnect, reboot and reconnect and hope that over a few days the exchange picks up the better connection speed.
However, about 2 weeks ago the broadband completely lost connection for about 22 hours. My wife works from home so we needed it up, even at dial-up speeds so that she could use email. I contacted the call centre in India (who weren't much use) who said they couldn't find anything wrong with the line and suggested I call the UK tecchies. Funnily enough, I had just called them up when I noticed that the broadband was back on. An amazing coincidence...
Anyway, I then did the usual - wait a day or so to see if it improves, re-set the connection so that my ADSL settings show a Downstream connection of 2000+ kbps and then wait some more for the exchange to catch up and bump my profile up to its maximum. That bump-up hasn't happened and today the connection is dropping out again, pushing my downstream connection down to 600 kbps. But for all this time we've been stuck at between 100-125k actual download speed.
I've got files I need to download, my wife has work to do from her laptop and I have 2 kids with homework projects to research. 100k is painfully slow, especially when more and more websites have flashy ads that probably load instantly on high-speed connections but take up to ten seconds for us. Why are downstream connections at exchanges allowed to fall to 100-125k, particularly when it will take DAYS to bump up (if you're lucky)? Having a minimum speed of 500k would at least allow you to work with the internet.
And why won't my connection automatically increase at the moment? If it's to do with flaky line connection, why has it deteriorated?  I had an engineer out about a year ago to find out why my connection was poor at that time and it turns out there was a bit of internal wiring that was causing the blockage - the connection to my house was a reasonably strong 2mb. I haven't touched my internal wiring since we sorted it out, but every now and then the BT Broadband connection just nosedives.
Current connection status (was 2400k, dropped to 1300k, dropped to 608k just as I was accessing the forums):
Line state Connected
Connection time 0 days, 00:28:48
Downstream 608 Kbps
Upstream 448 Kbps
ADSL Settings
VPI/VCI 0/38
Type PPPoA
Modulation G.992.1 Annex A
Latency type Interleaved
Noise margin (Down/Up) 25.9 dB / 21.0 dB
Line attenuation (Down/Up) 56.2 dB / 31.5 dB
Output power (Down/Up) 1.1 dBm / 1.5 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) 6 / 4
CRC Errors (Down/Up) 84 / 34
HEC Errors (Down/Up) 71 / 43
Error Seconds (Local/Remote) 6 / 4
But my actual download/upload speeds are 125 kbps & 345 kbps (using Broadband Speed Checker rather than the BT version cos its a lot quicker when download speeds are this poor).
I live in a village a few km from the Stubton exchange in Lincs so don't expect a brilliant connection, but this is getting pretty frustrating. If any of the mods can have a look at what may be happening on the exchange (and possibly fix it) I'd be very appreciative!
Cheers
Nick

Answer 1

Yes, to be honest I was a little surprised myself. But it absolutely didn't connect when plugged into the test socket (I even tried to force a connection from the Home Hub manager but it wasn't having it). It is definitely the master socket. The only extension is a small piece of (engineer installed) phone cable to link the hub and the master socket (because the socket and mains power are unhelpfully on opposite walls of the hallway).
I ran the Java download for Google anyway and it only took about an hour. The speedtester results are as follows:
 Download speed achieved during the test was - 109 Kbps
 For your connection, the acceptable range of speeds is 50-250 Kbps.
 Additional Information:
 Your DSL Connection Rate :2560 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
 IP Profile for your line is - 135 Kbps
I don't as a rule disconnect / reboot the hub; today it has been dropping off on its own, while several days ago I tried a few reboots just to try and get a connection.
Additional info - my exchange is actually called Claypole Fenton (or vice versa). Whatever, my profile has probably been welded to 135k for days and days.
Cheers
Nick