If Sky have decided there's a problem at the exchange then don't hold your breath.

I have been told there's an ongoing problem at my exchange. They did at one point phone to say it was fixed but then later changed their mind and now deny anyone was ever told it was fixed. Now all I can get from them is that there's a problem and BT need to fix it. However BT are taking an unnervingly long time about it and I suspect that Sky have forgotten to tell BT.