Good afternoon 
Long time listener, first time caller!
I have recently replaced my temperamental old dumb thermostat with a Hive SLT3d with the aim of using it with Home Assistant. The SLT3b model is touted to work with both ZHA and Zigbee2MQTT and the SLT3c with Zigbee2MQTT so I was hoping the newest model would work similarly. Alas, I was wrong!
I followed the instructions for previous models to pair with ZHA. The receiver (SLR1c) pairs OK, however, when I attempt to pair the thermostat it sits in pairing mode. After a minute or so both ZHA and the receiver think the thermostat has been paired (the receiver shows a solid green light and the entity appears in HA, though all the entity values are Unknown). I attempted the fix described here (essentially wait and try again), but with the same result.
Has anyone had success with this newer model? I think my next step will be to try with Zigbee2MQTT.
Core: 2024.9.3
Supervisor: 2024.09.1
Operating System: 13.1
Frontend: 20240909.1
UPDATE: Zigbee2MQTT worked perfectly!