Think I posted this in the wrong section earlier...
I think it t'was me with the reference to a Thai/Intl angle for this Harry Potter poster. It's not the same poster tho, it's only single sided and approx. 27 1/2" x 39 1/2". The difference I spotted is that this one has more of the image round the sides of the poster (note how much space is on the right of Hagred)...

This is only the auction photo, but when it arrives I'll take a better one and see if there's any legitimacy issues with it!