Initial inspection revealed that the floor was severely water damaged under the rear vanity basin, along the rear edge of the trailer, and underneath the shower cubicle. Cause was various copper pipes, rear window, and 'tool box' hatch seal leaks.
So the old carpet ( and linoleum tiles in the bathroom area) was removed to determine the state of the rest of the floor area. It revealed several layers of floor coverings over the years, but fortunately most of the floor is salvageable.
The decision was taken to remove all the crud from the floor surface, repair / replace as necessary, and fit a bamboo floating floor.
To do it properly, it meant stripping the interior ..... here we go again!