Sometimes (usually at the same time at 22pm) i hear all thermostats adjusting something, making noise, but they're turned off - why is it happening?
I haven't got Tado yet (still trying to find out which system to go for), but I have some old HomeXpert semi-smart valves, and they do the same thing once a week, so this may be the same:
They're completing a single cycle from fully closed to fully open, simply to "massage" the valve pin. The valve pins tends to get stuck when being unused for a long time (e.g. when heat is turned off for the whole summer). By cycling them once in a while, this is avoided.