Location Ideas

First scene, street arrest
Idea 1
Some old streets around the trinity market area or behind the deep look old, empty and rundown. These may be suitable to represent somewhere a drug dealer may have been found lying low. I am familiar with these locations though need to get pictures to find the most suitable area.
Idea 2
Indoor, warehouse looking building
Though this would look effective it may be difficult to find. It would make sense to film in an indoor area like this and also make for better sound quality than outside but again, finding a safe, legal location to film in wouldn't be easy.

Bosses Office
Idea 1
Offices within college
With minor alteration (getting rid of items that make it obvious that the filming is being done in a college) a college office could be made to look like a believable detectives office. If it is allowed by college staff this would be the easiest option.

Idea 2
Heavily altered room 
A room with a computer and/or desk could be altered if the effort was put in. The difficulty with this would to make it look believable so that it isn't obvious the room has been deliberately altered and doesn't look like a home enviroment.

Idea 3 
Actual Office in a workplace
Whilst probably the most believable, neither of my parents work in a place with an office and it would be difficult to get access to one other ways and filming time in an office like this could be restrictive and difficult to get re-shoot time.

Northcott's home
Idea 1
Living room of any house
This doesn't really require any effort to make believable though the lighting may need to be altered depending on the mood of the scene.

Chase Scene
Idea 1
Same streets as first scene
Could be same area, streets easy to film in.

Corridors
Any college corridors with either blank walls or with posters or leaflets you would find in a detectives office would work fine.