ADSL Noise margin too high

[#1]

Hi,
At the moment my noise signal margin is at 15db, however previously it was around 7db, as a result my sync speed has dropped back to 6080kb previously it always synced at 8120kb.
COuld anyone at plusnet tell bt to reduce this back to 6-7db please?
thanks

[#2]

Hi there,
This isn't going to be the answer you were looking for.
Because I have already got BT to reduce your target SNR after it having risen previously, they will not relower it because it will be increasing for a reason.
Does it remain static throughout the day, or does it fluctuate?

[#3]

it remains static, however for a few weeks after the engineer did somthing at the exchange it went back to normal (7db) but now its gone back up again? for some reason?
its defintly not internal wiring! the last time 2 engineers came round to check that.