My MY18 handbook says it's on the front of the right side camshaft cover and on the left side rear of the engine casing (looking from the driving seat).
I had to go “fishing” with a side facing endoscope to get the photo of the engine serial number. This one was at the rear left corner of the engine and was found when the endoscope was pushed through the square notch circled red, looking from above.
Without taking the engine out, I don’t know how I would have found it.
Well I hope it is the engine serial number!
I also found another engine number plate on the right side of the engine that was easily accessible. This had the same serial number but without the HGFHH. It was hiding behind some pipes. Shown as picture 4.