When this episode was originally broadcast in the U.K., it was done so using Dame Agatha Christie's original title of the novel that served as its source material when published (except in the U.S.): "4:50 From Paddington". When this episode was broadcast in the U.S., the title of the episode was changed to "What Mrs McGillicuddy Saw!" since that was the title of the same novel when it was published in the U.S..
When the character of Bryan Eastley, played by Michael Landes, is shown standing on the drive in front of the Crackenthrope manse, he is wearing the uniform of a US Army Air Forces officer. The patch on his left shoulder is that of the 9th Air Force, which was moved to England in October of 1943 to prepare for the invasion of Europe. He's wearing captains bars.
The newspaper Mrs Mcgillicuddy is reading is backwards.