There were two Xmas offers; for staff friends & family and also Tesco's staff friends and family, but these expired on 17th December. I am not sure if they have other offers running throughout the year, but these offers were for free HD box, free insallation, free HD pack and half price on all packages. The Tesco staff offer did not include free HD pack.
As previously stated above it is a good idea to give Sky a call and request 12 months half price channels as I have seen on another forum that this worked. However, if there are any better offers running during next year you will miss out on them. So it is a hard one to call.
James