For Manchester scenes (filmed on actual streets in the USA), any overly "American" curbside items (like certain fire hydrants) were hidden by dropping bottom-less slatted metal trash cans over them and then adding prop "English" rubbish; however, extras and crew unaware of this subtle artful touch continuously filled the apparently-normal-looking receptacles with their own trash. Between filming sessions, rueful set dressers would have to remove a foot-high layer of discarded plastic water bottles (and then reset and fluff the "official" rubbish).
The plot is set in various international locations: Manchester (United Kingdom), Samarra and Balad (Iraq), Qatar's US Military Base, Amman (Jordan), Amsterdam (Netherlands), Langley and Washington DC (United States), Dubai (United Arab Emirates), Incirlik (Turkey), Vienna (Austria) and Dar'a (Syria) but the actual filming locations were only Morocco and United States.
For Manchester Scenes (filmed in a gritty and real American slum), actual English "police line" tape was used. Its distinctive blue and white coloration contrasts with US-style police tape which is yellow with black text. Comparison was easy because occasional stray bits of American police line tape from past actual crime scenes were among the real neighborhood's windblown street debris littering the edges of the filming area.
Carice van Houten played the character of Roger's wife Gretchen Ferris, but all her scenes were deleted in the final cut. The movie does provide dialogue that distills the story in the book, when Roger says they are getting divorced because "I was a bad husband and she was a worse wife".
Some performers in the exterior Turkish Cafe in Munich Scene were stage-reading actual Arabic newspapers. The more-attentive among them were indeed reading from right to left (most noticeable when they turn a page).