You should post on that thread so that you can follow what is happening. A modertor is aware of the problems on that thread and I would imagine that he will chase it up and post back updates if he learns anything. It may be a capacity issue at the exchange which will need to be investigated by Openreach.
It's up to you but I suspect you won't get much more than what I have given you on this thread.
As you have seen from the link to the other thread, this peak time slow down seems to be a major problem for BT, its been going all month, and it seems a nationwide problem.
From what i believe the bt speed test takes the max speed on burst and not the average speed like all the others do,, most will give a burst but then settle on what your REAL speed is,
Bt speed test is about 12 MB above every other tester i have used so i dont believe a word of it, I am trying to get a reset just now as i heard the dlm is limiting me and probly always will ..