Unable to get Warmup sensors to become available in HA

I have the Warmup under-floor heating integration installed in HACS. In the custom components folder there is a warmup folder, with 5 subfolders including a warmup4ie folder containing 3 files including warmup4ie.

In configuration.yaml I have the following (including the two different methods of listing sensors that I have found):

# Warmup Integration
climate:
  - platform: warmup
    name: xxxx
    username: [email protected]
    password: xxxxxx
    location: xxxxx
    room: Kitchen
    
# sensors:
#   - platform: warmup
    # sensors:
    #   temperature_Kitchen_air:
        # friendly_name_template: "{{ states.climate.kitchen.attributes['friendly_name'] }} Air Temperature"
        # value_template: '{{ states.climate.Kitchen.attributes["air_temperature"] }}'
        # unit_of_measurement: "°C"
    #   temperature_Bathroom_floor:
        # friendly_name_template: "{{ states.climate.Bathroom.attributes['friendly_name'] }} Floor Temperature"
        # value_template: '{{ states.climate.Bathroom.attributes["floor_temperature"] }}'
        # unit_of_measurement: "°C"
        # specifying unit_of_measurement helps HA localise readings (e.g. convert to Fahrenheit on your display)
#alternative sensor setup
platform: warmup
sensors:
  temperature_kitchen_air:
    friendly_name_template: "{{ state_attr('climate.Kitchen', 'Kitchen floor') }} Air Temperature"
    value_template: "{{ state_attr('climate.kitchen', 'air_temperature') }}"
    unit_of_measurement: "°C"
  temperature_kitchen_floor:
    friendly_name_template: "{{ state_attr('climate.Bathroom', 'Bathroom floor') }} Floor Temperature"
    value_template: "{{ state_attr('climate.kitchen', 'floor_temperature') }}"
    unit_of_measurement: "°C"

My problem is that although the two sensors show in the list of enity states in developer tools they are permanently "unavailable’. I’ve seen the platform specified as “warmup” and “warmup4ie”, but neither results in an “available” entity state.

Some pointers on what I have done wrong would be appreciated.
Many thanks