Also.. for reference.. The channels you get free on Sky are part of a network called "Freesat," I believe. "Freeview," is a seperate venture..
While many of the channels are free on both, and there is some overlap, there are some differences.. like this.
I think E4 are tied into a contract with Sky, and they're having to compensate them by giving any royalties they would get from being on Sky, back to Sky.. or something? not sure..