The UFH in my conservatory is too hot/cold. Should I re-program the whole system?

No. Simply use the “down arrow” (bottom right of the thermostat) to reduce the temperature to your requirements and press the “comfort” (sun) button for three second (until the sign appears in the LCD display). This confirms you have reset the comfort temperature setpoint. To increase the temperature simply use the “up arrow” and follow the same procedure. This information is available on the programming instructions issued with each thermostat.