Shower bars (City road S2)

I had my shower bar changed not long ago to the silver one on the right in the picture but it had less power than my old one. So I bought the other one as seen from my eBay pictures but it didn’t fit, eventually i bought one from screwfix which works fine. So one has little use the other none and a shower head that came off with the old shower bare and still works but has signs of use. Many thanks.