Crosswater Thermostatic Shower

Have had 2 Crosswater showers recently installed (Kai 2 Lever with handset & Diverter) and Watersquare handset & diverter) My plumber doesn’t seem to have a clue how to set the temperature correctly and has left us with a setting that gives us only warm/hot water and no cold at all. We have a Worcester Bosch combi boiler.Not really happy with these settings. Would be really interested to hear solutions from plumbers that have fitted Crosswater products. Needless to say the instructions are useless on both products and the Crosswater Tech team are no help at all. I’m in South London