Another Possible Line Fault?

[#1]

Phone line faults were fixed last Thursday (14 May), connection was reset and everything was fine till Tuesday, am now suffering persistent drops during the day.
The connection drops appear to stop after 6pm. When the engineer visited he did say that they had been having issues with the green box in the street that I am connected to.
I have noticed that the SNR margin on download has dropped from 6.5dbn to 3.5dbn and my download speed has gone from 9.5mbs up to 10.5mbs.
How long will it be for my connection to be classed as unstable and my connection speed downgraded?

[#2]

The line actually looks much more stable now, I can see that yesterday and Tuesday had poor stability:

[#3]

I was expecting the drops to continue today but they haven't, I thought they were random drops but looking at the graph am thinking they aren't random.
Will have to wait and see I suppose.

[#4]

Suffered another load of drops between 5.30pm and 7pm.
So annoying.
If its that intermittent they will not be able to find the fault.

[#5]

Have received an e-mail from PlusNet, they are going to turn on interleaving to see if that sorts out my issues, we don't do online gaming so hopefully it won't cause us any issues.
At the same time I received the e-mail (5am), I noticed that our connection dropped and since then our upload speed has dropped along with a raised SNR margin.
Upload
SNR margin - 22 (previously 9)  upload speed - 0.3mbs (was uploading at approx. 0.9mbs)
Download
SNR margin - 2.4  download speed - 10.3mbs
We don't do much uploading so not sure if this will affect us much.
Will have to see how things go.

[#6]

I hope that sorts the issue out, keep an eye on it and let us know