I bought season one yesterday from Game in Wandsworth, London.
Got home, no free poster.
Went in today to see if they could find it for me. None of their copies have posters, despite it stating quite clearly on the box that there's a poster with it.
The guy behind the counter acted like I was insanely petty for wanting the poster and incredulous when I demanded a refund, then, as they hadn't sold me the full thing.
They're always really iffy giving refunds on PC games, because they're convinced everyone is a criminal pirate-y pirate.
Anyway -- no boxset for me; has anyone else had no poster problems in the UK??