Corrected entry: The intro scene shows the thief hanging from the skylight trying to steal a gem. She escapes where she came in and yet the next scene shows her walking inside the museum. This scene doesn't make sense because she already had an effortless exit on the rooftop.
Corrected entry: In the episode, because the Doctor was not around as he was killed in the alternate reality, all the present day invasions that he stopped in the normal reality happened. However, since his death was before many invasions in later seasons in the normal reality that were chronologically before his death (for example, The Carrionite invasion in 1599) the Earth should be already destroyed. Therefore, he couldn't die on Earth, so it would be a paradox that would erase his timeline.
Corrected entry: In the scene where Donna is examining the room Lady Clemency Eddison had kept locked for the past 40 years, there is a teddy bear on the bed. However, the story takes place in 1926, meaning the room had been locked since 1886. Teddy bears were not invented until 1902.
Corrected entry: You learn that there are three different types of Oods you can purchase: The Normal Slave, The Charming Slave, and The Comedy Slave. The Comedy Ood said "D'oh" when he was talked to, which is a reference to Homer Simpson's catchphrase in the famous comedy show The Simpsons. However, this is in 4126 A.D., so how could they possibly remember a character in a TV show that was over 2000 years ago? Even assuming that this show went on for another 100 years, which is unlikely, it would still not make any sense. And it's not even that a few people remember such an ancient show, it's everyone in the room (they all laugh when they hear this) - which consists of approximately 20 people. We can't even remember characters from 20 years ago (well, most of us), so the fact that they could remember Homer Simpson is a mistake.