Continuity mistake: Harry drives away from a crime scene and his rear numberplate is visible as D703 VAN. We then see Harry in his car from the front, and the numberplate has changed to E160 HLT. (00:21:18 - 00:22:31)
Factual error: The story is set in the 1850s, but when Greshambury Manor is shown at night, it is obvious that the front of the building is illuminated by electric lights.
Factual error: You can see the Unicredit Tower on the Milan skyline - the episode should be set in 1997 but the unicredit tower was built in 2012. (00:31:00)