shower diverter

I would like to identify this old bath/shower diverter so that I can obtain the correct washer and maybe an exploded diagram before tackling the rather awkward job. To explain how it operates, the upright piece on the left is the hand shower, its hose (and connection to the diverter) pulls up to...

Hi, Can someone advise me on how I remove my shower diverter pictured below? I need to try and fix it as it has stopped diverting water between the shower and bath which I think may be due to limescale as we have had this issue elsewhere. I can't work out how to remove it though, there is no...