Climate components won't display - even demo?

I’ve been trying to get the broadlink IR climate component working on my setup, but after several failed attempts to get anything to display I started to do some troubleshooting and wanted to get at least the demo client component working and take it from there. In theory this is just a dead-simple matter of putting two lines in the configuration.yaml file, but it isn’t working.

I’ve added the below two lines to my configuration.yaml, and commented out any other climate related code. However, I don’t see the climate component on either the standard view or the lovelace view. Any ideas what might be going wrong, or other things I should check?

climate:
  platform: demo

Resolved:

It seems the “restart home assistant” button in home assistant wasn’t working, nor was the reload core button etc. I happened to have to do a hard reset (unplug & plug) today after it failed to get an IP after the router re-booted, and once it came back up the demo climate component is shown.