Does CloudFlare only work on WWW DOT?

Does CloudFlare only work on WWW DOT?
Appears a plain domain (without www.) won’t work.
Please can someone confirm/explain this to me?

The external domain
We have a domain with an A record to our server IP.
A CNAME record cloudflare-resolve-to to our domain
A CNAME www to www.ourdomain.co.uk.cdn.cloudflare.net.

You seem to be on a partner setup (right?) and these are typically configured in a way that only “www” goes through Cloudflare. The naked domain goes straight to the host, who however redirects to www.

Thanks for the answer. Yes we are on a partner setup with SiteGround.
This suggests naked domain could work through cloudflare by other means.

An example would be helpful.

You will need talk to your host in this case. They are in control.

Alternatively disable Cloudflare on their end and sign up for a full account.