I've been told that you can order this poster from the following company:

Mailed Music and Video
15-16 Thomas Street
Chepstow
Gwent
NP6 5D11
England, U.K.

I got this news from a fellow in the UK who ordered the poster from there.. I don't know the specifics though, so you may just want to write to Mailed Music and Video and let them know what you're looking for!