When Martin and Philomena arrive in Washington, they are staying at the Washington Hotel, observable by the TV in Martin's room, which shows the big W for the Hotel. The Hotel's most interesting facet is its rooftop bar, which has the best view of the White House and Washington Monument of any DC Hotel.
While visiting the convent, Martin Sixsmith sees an autographed photo of an American actress on the wall and asks if it is Jayne Mansfield (and is told it's actually Jane Russell). A character who appears later in the film, Pete Olsson, is played by Peter Hermann, who is married to Jayne Mansfield's daughter, Mariska Hargitay.
In the United States, the MPAA gave the film an 'R' rating for ambiguous usage of the "F-word" (usually, only one non-sexual utterance of the word is permitted for 'PG-13'). A lengthy appeals process ensued, with producer Harvey Weinstein and actor/writer Steve Coogan testifying at the hearings in Los Angeles. The Weinstein Company won their appeal for 'PG-13' on November 13, 2013, nearly a week before the film's scheduled theatrical release.
When Coogan's character is holding the photo of Philomena's boy, and they show a close-up of the photo, it is the same close-up with Philomena's thumb in it, that we saw earlier, not a man's thumb.
Martin Sixsmith: Its funny isn't it? All the pieces of paper designed to help you find him have been destroyed, but guess what, the one piece of paper designed to stop you finding him has been lovingly preserved. God and his infinite wisdom decided to spare that from the flames.