If you know the general area of leakage, degrease it well and when ready, document the leak when you've found it by running the car 10 mins to simulate the previous observation. The cleaner engine should allow you to determine the source/s of the leak.

The only part I can think of, in front and below the turbocharger, is the wastegate hose, or the large U-tube.

Just to be clear, you say this is on the left side, when facing the engine. From the car's point of view it's the right side.