i bought a sky hd box as a spare box and simply asked sky to set up the multi room package

i was getting he full deal on the skyHD box upstairs, even getting the free to air hd channels for free (ok, bbcHD and channel 4HD so not really a whole package but you get the point)

i later put the hd box downstairs and simply got the cards switched over (you have to use the main card in the main box, not the bedroom box i was told) and upgraded to hd

so as long as you have your card paired to the box it doens't seem to matter what box you use