Im sure if you told them about her back problems you could get a exit row seat. As some one else said, when the skybeds fold down into the back of the seat in front, your basically stuck in the bed for the night! lucky i had a aisle seat!. I would choose QF Skybed, but i would say that BA's seat arrangement might be a bit better when in reclined position though. Because even if she does get E or F she can still get out.

Heres what i was lookign at
http://www.seatguru.com/airlines/Bri..._747-400_A.php