Template Switch + Television Icon

I’ve set up a template switch in my configuration.yaml so that I can customise the icon showing in lovelace from the standard flash which switches default to. The switch toggle works fine but the specified icon is proving problematic.

If I remove the icon_template block the standard flash on/off works fine but I want to replace that.

switch:
  - platform: template
    switches:
      tv_toggle:
        friendly_name: "TV"
        value_template: "{{ is_state('switch.tv', 'on') }}"
        turn_on:
          service: switch.turn_on
          target:
            entity_id: switch.tv
        turn_off:
          service: switch.turn_off
          target:
            entity_id: switch.tv
        icon_template: >-
          {% if is_state('switch.tv', 'on') %}
            mdi:Television
          {% else %}
            mdi:TelevisionOff
          {% endif %}

However I cannot get this icon showing in lovelace and I don’t believe that it’s a new icon either (?). ui-lovelace.yaml:

    - type: button
      name: TV
      entity: switch.tv_toggle
      show_icon: true
      show_state: true
      tap_action:
        action: toggle

I’ve also tried the TelevisionClassic/TelevisionClassicOff icons but they don’t work either.

I’ve restarted and recreated home assistant (docker) several times and cleared my browser cache but no joy.

Any ideas?

The icon names are all lowercase.

mdi:television and mdi:television-off

Doh! Many thanks :blush: