Off topic:
I had gone down the other path: (which is quite unreliable/difficult)
On topic:
Had a little time to test, got some more info, HA is actually detecting it as a thermostat! On first look it seems like the accessory info is getting lost or badly imported.
2018-07-22 13:08:03 DEBUG (Thread-19) [homeassistant.components.homekit_controller] Discovered unique device 02:FC:16:6D:96:FC
2018-07-22 13:08:03 INFO (Thread-19) [homeassistant.components.homekit_controller] Setting up Homekit device YT4710WF1003
2018-07-22 13:08:04 DEBUG (Thread-19) [homeassistant.components.homekit_controller] Found accessory-information
2018-07-22 13:08:04 DEBUG (Thread-19) [homeassistant.components.homekit_controller] Found thermostat
2018-07-22 13:08:04 INFO (MainThread) [homeassistant.components.climate] Setting up climate.homekit_controller
Using the homekit_python script I was able to get/set target temperatures etc with the commands:
python3 -m homekit.put_characteristic -f "hk-02:FC:16:6D:96:FC" -c 1.13 15
(ha) ha@ntpc:~/homeassistant/.homekit$ python3 -m homekit.get_characteristic -f “hk-02:FC:16:6D:96:FC” -c 1.12
{
“characteristics”: [
{
“aid”: 1,
“iid”: 12,
“value”: 25
}
]
}