I had same problem. Needed to remove entire valve . Removed all wrap around seats in salon. After many, many measurements I cut a 5”x8” hole in the aft bulkhead. Precisely behind the new cut out was the shower valve. Was able to remove and repair.
We did a three hour run without carpeting. Very little difference. Low noise, low heat on floor. We are trying this material as a experiment. Bought from E-Bay. 6mm Eva Foam Teak. Has a adhesive backing. Easy to cut with sharp knife or scissors. Like the look but what we do not know is how well...
Problem solved! I had to take out the entire shower control valve. Base included. On the bench I removed the brass plug on the bottom of the valve. I discovered a black hard substance ,that blocked the out port by 50%. I had to ream it out with a drill motor and a 1/4 inch drill bit...
Found it! The line that runs from the control valve to the fitting that attaches to the metal flex hose has a big restriction. Now to figure out how to get at it!
Thanks everyone!