This post is not for GoSix to read. (DH secrets revealed.)
Old Coot, (who owes me a cup of coffee), said the answer to my problem, (water pump making noise when I used the toilet at night) err, the DWs problem really, which made it my problem, was to isolate the water pump.
From the factory, it had been attached directly to the wet bay back wall which is metal. It was on rubber grommets but nonetheless it was loud and annoying to use, the sound carried through the coach and anyone nearby could here it.
Last year I replaced the original pump with a high end SurFlow that among other things was labeled "quiet". Not much improvement.
So my friend that owes me a drink (OC) said the solution was to mount the pump via rubber grommets, on plywood and then mount the plywood via rubber grommets of its own, on the floor of the wet bay which is a softer material than the metal wall.
Here are the pictures which I provide least my friend suggest I did not actually do this project.
If Old Coot was right, the DW should be happy and if she is happy I may get ........ Well if that happens I'll owe him a couple coffees.