Just another data point to add on this - I bought a Apple Magsafe Airline Adaptor in Dixons at T5 before a flight a few days ago in WT+. It was £33, as opposed to £28 on Apple.com (typical Dixons being overpriced as usual!) but worked perfectly in the seat, and charged my Macbook Pro 15" (late 2007 model). However, it charged it very slowly - in fact the icon stayed as the 'plug' rather than the lightening bolt, which would indicate that it wasn't charging, however the percentage climbed up from 60 odd to 100 over the course of the time I was using it.