Same thing is happening to me day and night just getting about 2mb,sky has been doing all possible.
my router states 8124 DL and 7150 line profile, but phone call from sky CS this morning said in so many words they are jamming as many on the line as possible and who cares what speed you get.
My speed for about 3 years I think has been 7.5mb all the time now down to 2mb