Thanks for both answers. Based on that info, she's going to have a second HDMI cable run.
Good spot about the TV's power lead - but it turns out that she's already made provision for that separately, running power to a socket on the wall behind where the TV will be.
Sorry, thanks for all three answers!
I was just thinking about a network cable, too. I did a quick Google and Internet-connected TV seems to have had something of a mixed reception.
I started discussing it with my friend and it turns out that her router is right across the other side of the room, so direct cabling sounds a bit impractical. Unless - is there such a thing as a wireless receiver that could sit with the Sky and DVD boxes, and that be connected to the TV, acting like a kind of repeater?