I have an old freesat box which I use in my bedroom. I would like to upgrade to a hd version. It has been suggested that you can use an unused sky HD box or Sky multiroom hd box as a freesat box, no subscription to sky. I have looked a little online and that seems to be the case but I would like to double check. Has anyone done this? Any issues or is it as straightforward as just plugging it in, wire as well of course.