Revealing mistake: Florence and Humphrey are reading the article about the young Dexter Allen from the Hackney Gazette. Behind the article, Florence has her mail open. Amazingly enough, the names of the people she received mail from (Joshua, David, Faye, a Customer service) are the same ones as the victims in She Was Murdered Twice, season 4 episode 7 when one of the suspects opened it from a public computer. (00:30:45)
Revealing mistake: While they are checking out Matt Holt's discount Facebook page (Face-spaces dot com) on the computer, behind the browser window there's an open file with a fingerprint, and like in another episode of this series, it's a fingerprint not related at all to this case, but one from three years earlier, the episode of season 3 "Ye of Little Faith", this time from the victim of that case Natasha Thiebert. (00:26:30)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.