Entity shows 'unavailable' when adding two TRVs

[Moohan]

I've just discovered and set up Better Thermostat. I have Tado and then Moes BRT-100 TRVs in some rooms.

The Tado works fine, as do the rooms where I only added one TRV but in my living room we have two TRVs, this entity just reports unavailable.

Is this a bug or have I done something wrong?

• Working 'Tado' config - config_entry-better_thermostat-60f78ebe4235a57b2734fd03ffc4dbad.json
• Working 'Moes BRT-100 TRV' (single TRV config) - config_entry-better_thermostat-60f78ebe4235a57b2734fd03ffc4dbad.json
• Broken/Unavailable 2x TRVs config - config_entry-better_thermostat-7918b4b01890ad973ba3e2974757902b.json

[Moohan]

This seems to have just started working...