We are having issues with the shower over bath not draining and I finally go round to crawling under the house to investigate.

The u bend was clear but I noticed that there was a bit of what looked like gunk from the top and when I gave it a pull it turned out to be some concertina pipe.

It looks like the bath tub drain is connected to the you bend via an internal concertina pipe (didn't have my phone).  It also looked like some of the floor boards under the bath were wet.

The bath itself is impractical and would really like to replace with a shower.  The bathroom sink is also impractical. 

Has anyone worked with a bathroom designed that they would recommend?  No idea of the budget we want quality but not super high end.