Harry Potter Azkaban UK Quad poster

Not really sure where to put this but if one of the mods wants to move it then please do so.

Does anybody know where I could get a double sided UK quad (that's the 40" x 30" size) of the theater poster for Prisoner Of Azkaban? It's the one where Harry, Hermione and Ron are standing with the 'Dementor's in the woods' scene behind them. There's one on ebay right now but it's £25 plus shipping which I think is a bit steep. Maybe you have a spare you'd like to swap or sell or you know of somewhere on the interweb that sells them? I've trawled through quite a few sites via Google but so far without luck. I have all the other Potter quads (including Phoenix) and I cannot imagine how I didn't pick this one up. Goes without saying it must be in mint condition though (rolled up, no tears or scuffs and definitely no pin holes or blu tack splodges!)

Thanking you...