@Scotland
have you had any luck with this?
I have relatively new ecodan installed with wireless thermostat and it works fine.
I just installed UH8 for my UFH and when I wire heat demand from it to pump main panel it doesn’t fire up.
Current thermostat receiver is witted to IN1 so it should be as easy as taking two wires out and connecting two form UH8. Should be 5min job but….. it doesn’t work!!!