I knew before it was somewhere at the rear left. Saw 2 pipes that run from the intake manifold to the rear left and the 2 goes into the body from underneath.
I do not quite understand you when you said "inside the left-hand rear wheelarch liner". Could you elaborate? and provide some details/steps to open up this area. Do I get to this area by taking out the rears seats or do I start from the bottom of the car?