Factual error: During the scene when Harry and Hagrid are on the motorbike going through a tunnel, the bus signals that it is going to Dartford. Both of the tunnels at Dartford carry north-bound traffic, going away from Dartford - all south-bound traffic, towards Dartford, travels on the bridge (visible in some shots). No traffic enters the tunnels heading south-bound towards Dartford.
Suggested correction: During times of high winds, the Dartford Bridge is closed, and one of the tunnels does, in fact, carry southbound traffic.
Factual error: In the scene where Harry and Hermione are dancing in the tent, a radio is on. The song played is "O Children" by Nick Cave & The Bad Seeds, which was released in 2004. However, Harry Potter and the Deathly Hallows takes place in 1997-1998, considering that later in the film the graves of Lily and James Potter give their death year as 1981. As Harry was one year old when his parents died, this means that he was born in 1980, and thus the film itself must, like the book, take place in 1997, when Harry is seventeen. This makes it impossible for "O Children" to have been on the radio at the time.