Low bandwidth and slow download speeds

Question

On a normal day, our router (a BT HomeHub 1.5) reports about 1700 kbps downstream bandwidth, and downloads at around 100-180 kBps from most websites.  On Saturday, after it reset itself several times repeatedly, the downstream bandwidth dropped to about 400kbps, and download speeds dropped to 20-30 kBps.  I did the usual of resetting the router (power off, wait 30 seconds, power on), with no effect.
After about an hour of these speeds with no change, I gave the BT hotline a call.  We did the usual checks (plugged into the master socket, all phones in the house passing through filters, line attenuator/accelerator attached to the master socket) and then she did a line test and couldn't find any faults.  I have since also done a quiet line test (17070, option 2) and couldn't hear any significant static.
I was advised to leave the router on for 24 hours without resetting it so the line could be reprofiled.  The router managed to reset itself overnight for Sunday morning, but has now been on for over a day, with no change in connection quality.  We've done reprofiling once or twice before, and generally it fixes itself in a few hours.
Today, I ran btspeedtester and checked the ADSL Line Details page of the router.  You can see the results at the bottom.
So, is there anything I'm missing on checking (I find it highly unlikely that 'leaving it alone' for 3/5/10 days is going to do anything other than waste my time; see almost every other speed problem topic in the last few weeks to notice that there is a trend of problems not fixing themselves if you just wait ), or should I go ahead and send in a customer support request for the mods here?
 Download speedachieved during the test was - 231 Kbps
 For your connection, the acceptable range of speeds is 50-500 Kbps.
 Additional Information:
 Your DSL Connection Rate :416 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
 IP Profile for your line is - 350 Kbps
Link Information
Uptime:
1 day, 7:24:42
Modulation:
G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:
448 / 416
Data Transferred (Sent/Received) [MB/GB]:
465.37 / 2.18
Output Power (Up/Down) [dBm]:
11.5 / 12.5
Line Attenuation (Up/Down) [dB]:
31.5 / 55.0
SN Margin (Up/Down) [dB]:
14.0 / 15.0
Vendor ID (Local/Remote):
TMMB / ALCB
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
2 / 0
Loss of Power (Local/Remote):
0 / 0
Loss of Link (Remote):
0
Error Seconds (Local/Remote):
22 / 0
FEC Errors (Up/Down):
0 / 5,876
CRC Errors (Up/Down):
0 / 156
HEC Errors (Up/Down):
0 / 128
Line Profile:
Interleaved

Answer 1

Well, since the router reset itself for no apparent reason again which makes it unlikely it'll stay on 24/7 for 5 days, here are the results from connecting it to the test socket.  Not much difference on our end.
 IP Profile for your line is - 350 Kbps
 Download speedachieved during the test was - 309 Kbps
 For your connection, the acceptable range of speeds is 50-500 Kbps.
 Additional Information:
 Your DSL Connection Rate :3680 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
Link Information
Uptime:
0 days, 0:02:29
Modulation:
G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]:
448 / 3,680
Data Transferred (Sent/Received) [KB/MB]:
301.00 / 1.37
Output Power (Up/Down) [dBm]:
11.5 / 19.0
Line Attenuation (Up/Down) [dB]:
31.5 / 54.0
SN Margin (Up/Down) [dB]:
14.0 / 6.0
Vendor ID (Local/Remote):
TMMB / ALCB
Loss of Framing (Local/Remote):
0 / 0
Loss of Signal (Local/Remote):
1 / 0
Loss of Power (Local/Remote):
0 / 0
Loss of Link (Remote):
0
Error Seconds (Local/Remote):
1 / 0
FEC Errors (Up/Down):
0 / 575
CRC Errors (Up/Down):
0 / 1
HEC Errors (Up/Down):
0 / 1
Line Profile:
Interleaved