Welcome to the community @Jillofalltrades
Yes, the domain name in your request was for latstudios.com.au and that is the IP and URL that was used for the cert request.
To get a cert for latgate27.latstudios.com.au you should change the domain name field in the request screen. Just having the cert name be latgate27 is not enough.
It looks like your domain latstudios.com.au is using a valid cert issued Dec3. A handy tool to check certs is this SSL Checker (link here)