Don't be scared by stats. They are fairly easy once you read a line at a time and don't think of them as a picture

. Until you understand the important lines of course, and then it's the overall story that matters.
The three important ones
for most lines are:-
1) The downstream and upstream
connection speeds. Yours are 4,576 and 448Kbps. On ADSL Max which you are on 448 is the normal upstream except on very long lines. The 4,576 downstream should at quiet times on the net be giving you somewhere between 3000 and 3800Kbps actual. At busy times it could be lower, but that is another matter. So on the face of it you should be getting nearly what you are used to, not 1Mbps.
2) The line attenuation basically shows the loss of signal strength due to distance from the exchange. Upstream is usually about half the downstream, for technical reasons, and yours is spot on.
This graph gives a rough idea of the expected range of connection speeds for various downstream attenuations. As you can see, yours is well down.
3) The noise margins, which provide a safety net for your connection. There is electromagnetic noise affecting your line all the time, like interference on a radio, and the level of actual noise varies 24/7. The noise margin is there to allow for noise to increase without you losing connection.
The normal value of the downstream margin should be well below your figure of 17.7dB. That is the main reason you are not connecting at or near 8Mbps as per the graph. It also inplies the underlying noise is not bad, but the variation is very large.
So what else is important in the stats? That is dead simple.
The error statistics!
Ignore the huge number of downstream CRCs - that is a known reporting bug in the Home Hub.
But seriously bad are the Loss of Framing, Loss of Signal and Error Seconds over a period of 3.5 hours.
I know you say you have done all the checks support have requested. It gets totally frustrating as they always want you to start from scratch and repeat them all. The trouble is they tend to have to read from scripts and aren't allowed to think for themselves. So I'm afraid you may have to go through some stuff again, or at least make absolutely sure you have done what anyone here suggests.
Before that though, I think if you have a relaxed read of all except the "Router locking up" page in my
Troubleshooting page some things that haven't been suggested by BT may come to light.
For a bit of background explanation of Noise margins and your speed, have a look at the Noise Margin and BT IP Profile pages. You are probably being badly affected by the Profile side of things, on top of everything else

.
So there's your homework

. I think if you take a deep breath you should be ok, as you haven't got someone on the end of a phone expecting you to do things and understand in an instant what you are being told. You have no chance of grasping or remembering it all in a day or so, but a lot will stick

.
Then you will be in a better position with regard to questions asked and understanding what is going on.