I am having issues with misfiring and plugs have carbon soot on them which seems to indicate running rich in fuel, air filter may need replacement and I will also attempt to clean air flow meter.

Does anyone have a photo which shows where the air flow meter is located in the engine of the N63 550i? Is there much work involved to remove it?

 

If you mean the Mass Air Flow (MAF) sensor, it's in the duct that connects from the air filter box to the engine, which runs right across the front, top side of the motor. When you open the hood, it's the first plastic duct you see right in front of you. Very easy to get to and remove/replace.