@Paul - Thanks for the info! Can't imagine things would be all that different between US and UK. In this case I have what I guess would be considered an advance, as well as the final version. The artwork is the same, but the title, tag line, etc are different, and each is on a different material.
@ Dale - Pretty sure it's not a subway. It definitely does not have an adhesive backing.
@Archie - Thanks for the info! I've always wondered about the large format posters found in IMAX light boards vs similar vertical formats like bus shelters. Perhaps this is one reason for the discrepancy.