Without a lining and the 2 holes partially behind the diagonal parts being plugged, water can come down inside the strut and come out in the same area as the filter.
The centre hole and unsealed clips is where it intrudes onto the engine.
Maybe just a freaky coincidence with the angle I was parked but definite drops of water on the foam a while back.
Since sealing mine using a 3m D-shape seal along the back of the strip and a solid ribbed rubber block along the bonnet recess to marry up - guess what....the water still collects!
But using the clips with seals, having the 3 holes plugged and lifting the bonnet just above the horizontal to let any water run away harmlessly down the windscreen means the engine seems to be staying relatively dry.