After Mitchell kills Stephen the coroner and starts smashing the place up, he pulls down a metal locker which lies at a right-angle to the coroner's body. As Mitchell and Daisy leave the lab, the scene cuts back to the coroner and the locker is now parallel to the coroner's body.
George describes Kemp as a defrocked Catholic priest. Catholic priests are not allowed to get married, but in a flashback to his time as a priest (seen in In the Morning, ep. 2.6), Kemp is shown with a wife and daughter.
While Kempe is described as a former Catholic priest, in the previous episode In the Morning (2010) his parishioners refer to him as "Reverend", while Catholics would call him "Father", and when praying over Annie, he holds an Orthodox Cross (used specifically in Russian Orthodox, Eastern Orthodox, etc. faith). A Catholic priest would never use such a cross.
When the clocks go back to GMT from BST, they always do so at 02:00 BST on the last Sunday of October, so by 19:00 GMT the Sun would have already set, yet when George runs home from Molly's school whilst changing, it is still light outside.
Vampire reflections cannot be seen, but when Mitchell and Daisy are in the cafe, their reflections can be seen in the picture frames behind them.