markjohnson102 wrote:

As well as asking for advice on a stud wall for pipes, the same
bathroom project will involve putting down a new floor over the
existing 1930s floorboards. Question: is it work putting down a board
first to make it more stable (floorboards are not that brilliant), and
if so, what's the best type of board to lay? Any advice you may have on
the best type of flooring to get would be appreciated too, since all
bathroom-rated manufacturers say there's won't suffer under these
conditions...

Most likely 6mm WBP plywood, but could depend on what type of flooring
you have on top

David