I was told that the cover inside the engine bay on the floor of the engine bay in the top third of said engine which has a very big electrical cord going into the area of the pelican bay is the where water ingressed hence now there is lots of silicon going around it in order to stop that.
The water was able to run along the cable through to the inside and then to the box but with a pressure washer the plate itself wasn't standing up to it.
Than again who uses a pressure washer on a £4.000.000 aircraft, I wouldn't use it on my £1.000 car.