I’m seeing 4 cycles per hour overnight in your screenshot, around 10 minutes per cycle, which might not ideal but I don’t think is very bad. Can’t tell if this is being triggered by the HP or something else in your system, so I’d suggest looking closely at the room thermostats, maybe find out their make/model and manuals.
It’s also curious why it’s running overnight - either the setback is being ignored, or the other thermostat is still calling for heat. What time does your set-back period end? 0445 perhaps? Is it set on the HP unit, or a programmable room stat? Have you checked that all the relevant clocks are set to the correct time (zone)?
The flow temperature looks to be following the curve I’d expect to see, keeping it at 37 through the night. It’s working harder from 0445, yet the flow temperature isn’t going higher. My guess is that the underfloor heating is staying on through the night (cycling), and then the radiators are coming on in the morning pulling more heat out of the system. [Based on some things you said in your previous thread]
We can at least see that your heat pump can scale down to a minimum power of 1 kW, which is good.