When they visit the House of Commons for the first time, the newspaper boy carries a poster "London motorist killed"; on the trial's first day, the poster hasn't changed-- or else a second motorist has been killed.
Early on in the film, as his parents take Ronnie to the train station, the 'scene setting' shot of the station is quite clearly contemporary to the making of the film. All the people are wearing clothes of the late 1940s. The woman have short hems and 1940s hair 'do's'. Pretty poor and unfathomable error given every effort was made to dress the characters according to the era of the film, at this point 1913.
When the film opens, a suburban train is coming into a station. The locomotive is in the livery of LNER (London & North Eastern Railway). Arthur Winslow alights having told his travelling companions that he has just retired from Lloyds Bank. When he gets home he shows his wife a pocket watch the bank gave him to mark his retirement. It's dated 1912, but the LNER wasn't created until 1923.
Seen in mirror of room where Arthur, Catherine, and Violet talked: Violet leaves through the door, and a crew-member's shadow is seen after door closes.