Options where speed is well below the estimate

[#1]

When I ordered fibre the agent said I should get 50Mb/s plus or minus 1Mb/s (you can ignore the last bit other than giving a bit of training)
Now that information came from the BT check as shown in the attached image
When the line was first connected the BT Engineer stated that I was in sync at about 48Mb/s
After several problems - now sorted - the sync speed was just over 40Mb/s with interleaving which will probably have reduced the speed and may correct itself but I will still get nowhere near the estimated range.
When I asked the engineer - the one who came out because of the fault - he said that their estimate was nothing like 50Mb/s and that was a Plusnet estimate (I didn't bother arguing)
Now from the distance to the cab and using the TBB chart  http://www.thinkbroadband.com/guide/fibre-broadband.html I am actually doing rather better given a line length of about 800 metres
Note that according to the Billion 8800NL the attainable rate is 52.8Mb/s
It appears that there is no chance that BT will accept a fault so how long should I leave it to see if the DLM will remove the interleaving and the effect of it before ringing to ask to be moved from 80/20 to 40/2 product

[#2]

You are doing very well. I sync at 47 Mbps on an estimated 450m line length. If the cause of the DLM intervening has now been resolved, I think DLM will act relatively quickly. My experience is that once the source of the problem is removed (in my case noise caused by homeplugs that caused a high level of interleaving to be applied), DLM will act within a few days. I know a lot of people say sometimes DLM takes weeks to act, but I can't help but think in these cases, there are still some issues (e.g. errors being recorded), that slows down DLM intervening to improve.
I think a lot will depend on the current error rates on your line.

[#3]

oldjim censor your phone number.
so your low end estimate is 50. plusnet were right, problem is these engineers tend to talk out their backside as an excuse to get out of the door, I had one tell me my estimate is for those next to the cab
the good news is we know your line will get faster if going back to fast path (or g.inp).
The question is will it move back? the answer lies in how many errored seconds you getting per day.  You need this to be under 144 a day.  If it stays under that then hopefully within 2 weeks it will change you back to a full profile.

[#4]

sod it - I uploaded the wrong picture - fixed thanks
At present about 70 per day although I have 274 on the upstream
Note I download 55GB yesterday so that may have affected things

[#5]

upstream doesnt matter, down and up treated independent from each other.
what you download doesnt matter either.
you can confirm upstream is on fastpath?

[#6]

Upstream is on fast path - interleave depth 1, INP 0
I would have though downloading a heck of a lot rather than just ticking over would have created the opportunity for more error seconds because of the higher number of uncorrectable RS errors

[#7]

I think there is a continuous noise chatter between cabinet and modem even when no useful data is passing.  There can be errors detected in that  When there is real data it replaces the chatter.  Not at all sure about that, though.

[#8]

whilst you looking good for a DLM recovery, I fear it wont last.  If you getting 70 a day whilst interleaved I suspect that will give you more than 2880 a day whilst in fast path so your line may end up going back and forth until g.inp saves it.  But lets wait and see first.

[#9]

It's not a "noise chatter" . It's a continuous stream of packets in both directions at the sync speed, whether data is passing or not. Think of sending to and receiving from a friend a letter every day. But you don't always put anything in the envelope.
The pattern of bits (header etc.) can be corrupted even with no data.