well i bought a Sky+ HD box off gumtree in preparation for having Sky installed in a few weeks time and decided to set the box up just have it in place so when the engineer does the multiroom setup, I will just tell him to keep the multiroom receiver in the box and I shall keep that as a backup, and to hook up the feed to the box I have bought.
whilst installing the Sky+ HD box i noticed the aerial in, currently I am using the built in HD tuner on my tv, but it can only view/record 1 channel at the same time, i assumed the sky+ hd box must have 2 tuners (since it has 2 sat tuners) and i could hook it up that to record one channel whilst i watch another until sky is installed.
i was rather miffed after unplugging the aerial feed and connecting it to the sky box, that i had zero feed, there is no built in digital freeview tuner at all never mind 2 of them, yet it has an aerial in.
but for some reason they have done it this way to feed the tv and sky around the house at the same time, useful i suppose if you have had your house wired up in this manner but i don't.
at least i know now why it has an aerial in feed.