Speed going down not up

[#1]

Hi there, I had my fibre installed a few weeks ago and during the first 10 days I had a lot of disconnects. The installer wouldn't put the router where I wanted and turns out I had a very dodgy RJ11 cable with loads of errors so I got lots of disconnects (as I needed to move the router a few times and change the RJ11 lead a few times too)
I now have everything set up pretty nicely, with a nice short tandy cable to the modem and I have had a rock solid 56Mb download on speed tests every time for a week.  I was expecting the BT DLM to go - "he's got a nice solid connection, lets try some more speed", but today I see the line has dropped and my BT profile has gone down, not up.
Is anyone able to confirm that my line is in good order? I have done everything humanly possible to eek out every last drop of speed but my efforts seem to get nowhere, and I am now paranoid my line has some kind of fault on it 
Must stop checking TBB quality monitor.....    I thought after moving up from 1.9Mb ADSL I'd forget about this kind of stuff!
http://www.thinkbroadband.com/ping/share/e3094b4d33b8d6c6d085573aeb1e4c66.html

[#2]

Hi there,
I've just checked your account and ran some diagnostic checks and can't see anything obvious I'm afraid.
I assume the line is working OK for calls and you can't hear any excess of noise on there?

[#3]

Hello - I've managed to get a corded phone and done some quiet line tests over the last few weeks.  There is a very low buzz/hum, but it is pretty quiet. Not silent, but you couldn't say it was noisy.  There's no crackling and it doesn't change with the time of day.
A day or two after the last post (middle of last month) my speed dropped down to 46Mb and has sat there ever since. I'm hoping that my line has been nice and stable (I haven't seen any disconnects in weeks) and my profile will go back up...
My neighbour who is about 25m along the road gets 70Mb although he comes straight off the telephone pole.  I suspect my line must be somewhat more circuituitous.
Do my line stats look good? Should I hope to get more or am I just on a bad line? When I first signed up I was estimated 60-80.
Thanks for any help/info.

[#4]

Well a couple of days after my last post (over a week ago) the village had a power cut and by BT profile has slipped further.  It's now down at 47 with an attainable speed of about 43Mb...
Is anyone able to get line stats please? My Plus net connection page is still reporting "Estimated line speed: 59Mb" which is giving me some hope that my line is not as good as it should be.
Thanks.

[#5]

I've attached your line stats.