1. Early in the episode there is a farmer wearing a wide brimmed hat. The date is supposed to be 1962, but the hat is obviously a Tilley, which were not made until the 1980's.
2. At the beginning of the episode, we learn that the "curiosity" was around in London in 1893. Around 9 min. H.G. says "in the words of my good friend Mr. Doyle: 'the game is afoot'," as she sets out to find the curiosity. Doyle wrote the original Sherlock Holmes stories, the first of which was published in 1890. However, Doyle only ever included the phrase "the game is afoot" in the short story The Adventure of the Abbey Grange, which was published in 1904.