At about 24 minutes, Arthur Conan Doyle is in the study of Chief Constable Anson. At one point, an image in which Anson is shown alone is reversed: His vest buttons backwards, his watch hangs from the opposite pocket, his drink is in the wrong hand, and he moves to his right even though we see Conan Doyle follow Anson's movement as if he had gone left.
The closing credits stated that George Edalji died in 1937. This is incorrect: he died in 1953. The error was corrected in later repeats of the series.