I paid about 4k In Manchester 9 years back, on a back to brick bathroom job, including changing the layout.
Bathroom costs on the refurb I'm currently doing come in at 9.5k . It's a pretty extensive scope of works. Lots of plumbing work (the room was previously a bedroom) , couple of custom elements, wet floor, and decent level of finish . So it's absolutely possible to come in well under 9k