Taken from sky's website
Sky+ HD: To get Sky+ HD, you require a Sky TV subscription, a Sky+ HD box and you need to subscribe to Sky+ HD by taking the HD Mix (£10 extra a month). Only compatible with digital satellite. Sky+ subscription required to use the Personal Video Recorder features of the Sky+ HD box (currently free while you subscribe to any Sky TV package, otherwise £10 per month). Sky+ HD box £150 when you take Sky TV and the HD Mix.
So where is the £75 deal?????????????