If we're going to write this as if the story is a cancelled DVD extra instead of a released webcast, we need to DAB accordingly. Thus, i suggest: P.S. (homevid)
Talk about it here.
P.S. was a proposed DVD extra that was envisioned as a live action coda to the events of the September 2012 portion of series 7, particularly the episode The Angels Take Manhattan. According to its writer, however, it was cancelled when an actor's availability fell through. Its storyboards were then animated, and narration was commissioned from Arthur Darvill. Ultimately the scene was made public by the BBC as a webcast that was uploaded following the broadcast of The Angels Take Manhattan. Narratively, this scene is meant to give Rory Williams's character closure, and by extension, show that he and his wife Amy Pond would live out a happy life in 20th century New York City. It also technically serves as Darvill's final regular performance as Rory.
The Doctor leaves with Amy and Rory after having dinner with them and Brian. A week later there is a knock at the door and Brian answers it. An American man stands there; he passes Brian a letter and walks in. Brian sits in the lounge and reads the letter revealing it is from his son Rory telling him that he and Amy are trapped in New York City fifty years before he [Rory] was born and they can never come home again. However he assures his father that they lived happily together for the rest of their lives, and adopted a son in 1946 named Anthony who is the man who delivered the letter. Rory also tells Brian that he misses him and loves him, and understands how weird it must be to have a grandson who is older than he is. Brian goes into the hall to see Anthony, who offers a handshake. Brian hugs him instead.
Home video release
To date, no home video release has occurred, with P.S. being omitted from both the UK and North American editions of the Series 7 DVD and Blu-ray box set.