Connection problems

[#1]

I transferred to Plusnet a few weeks ago, and was really pleased with the connection and service.  Unfortunately a few days ago I started suffering frequent complete loss of external connectivity for 15-30 seconds at a time.  The router appears to retain DSL connection throughout, but no packets are successfully received from the other end.  FEC/CRC/HEC error counts are rising on the router during this time.  My downstream SNR is usually between 1.1 and 1.6dB.  Connection speed is good, when it works, sync speed has been constant and have not experienced any line drops in 16 days.
I tried to use the broadband troubleshooter, but it just shows: "Please try using the Broadband Troubleshooter again in a short while." as soon as I go to it.  I've raised a question on my account a couple of days ago, but received no response.
Seems that the low SNR is likely to be the source of my problem, but I'd appreciate a second opinion and a response from PN.
Stats from a couple of days ago:
DSL Connection
Link Information
Uptime: 14 days, 2:47:18
DSL Type: ITU-T G.992.5
Bandwidth (Up/Down) [kbps/kbps]: 444 / 13,346
Data Transferred (Sent/Received) [MB/GB]: 382.43 / 1.97
Output Power (Up/Down) [dBm]: 12.1 / 0.0
Line Attenuation (Up/Down) [dB]: 19.7 / 35.5
SN Margin (Up/Down) [dB]: 29.6 / 1.2
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 8 / 0
Loss of Signal (Local/Remote): 3 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 185,190 / 0
FEC Errors (Up/Down): 0 / 1,544,548,758
CRC Errors (Up/Down): 4 / 77,133
HEC Errors (Up/Down): 0 / 1,818,293

[#2]

Hi there,
The easy one first - the reason the troubleshooter is failing is because you already have a fault ticket open as of the 4th, so it's already with our team
Odd that it's not dropping. I guess it's the same when you're connected directly to the router via ethernet as it is on wireless? With something like this I'd usually suspect wireless to be the culprit.

[#3]

Ah, good!  The troubleshooter seemed to dump me out before completion the first time around though...
The router's not very easy to get to so was only trying by wireless, but throughout I could access the router and a couple of other things on the internal network as usual while the internet wasn't accessible (hence watching the error counts going up!)
I've just had a reply to the CS question with a line reset to bring the noise margin back up to the target 6dB.  Hopefully that'll fix it.  Thanks, chaps