I think its worth pointing out that if your SKY+ box is inside a year old then you are contracted to keep it connected to the phone line, if you dont you will get a nasty letter from sky, then after so many nasty letters they will attempt to charge you for the full cost of the box, the phone line is part of the subsidised deal you sign up to.
I have just hit the year mark, however, it never stopped me taking the box away to the van with us, upon my return home i would always make the box do a call back to sky so that they had no reason to get snotty with me.
a forced call back can be achieved by pressing services,4,0,1 select, 6, this will first make the box call the satellite via the dish, then contact sky via the internal modem.
simple.