The character of Ben, was originally written to be Danny's right hand man, and share the same interests as him. However, due to this resulting in less dynamic within writing, the character was redrafted to be the polar opposite of Danny, which created more interesting dialogue options.
The scene in which Danny & Ben discover how much is in the case had to be re-filmed, mid way through production.
This was because director, Jordon Sendall, when watching the scene back during the edit, saw a lack of importance, in the way the scene was originally filmed/acted. Sendall, also did not like the location.
The scene was re-filmed & moved to the local boating lake, just by where Sendall grew up & lived, and went on to become one of his favorite scenes of the film.
When Necktie John (played by Adam Mannering) exclaims he has 'driven miles to get here' in the opening pub scene, he isn't lying. The actor, (Adam) actually did drive miles to be available for the film, from Kent to Great Yarmouth, where filming was taking place.