@bigthirst Hello - are you saying that the heating does not start at the time you have scheduled it to start or that it is not warming up in time?
@bigthirst OK - 2 options. You can try "early start" which you get in the smart schedule page of the app then settings in top right corner OR through the experience you have gained you could simply alter your start time.
If Tado is switching off the heating for long periods then a slow warm up time is expected with UFH, compared to radiators. An insulated concrete slab floor will take between 2 – 5 hours to warm up. The amount of time taken to reach the full temperature will depend upon the temperature the floor has been left at between heating periods. Contact Tado and ask if they can adjust the config parameters for your home.