It's often that you get something for nothing, but that's exactly what Sky is offering for the next few days . The telly company says that some customers can get a free upgrade this week, which will add 35 channels to their screens without paying a penny extra. It's a nice boost, but how do you get it and what's included? This freebie, which is available until Wednesday, October 16, instantly upgrades those with basic Essential TV packages to the more content-packed Sky Ultimate TV option at no