James, 

You are right. This feature does not exist in Xeams and is left out by design. It is very common to run into errors when HTTPS, which happens due to several reasons. For example, an error with the certificate. In that case, you will get locked out if port 80 redirects the traffic to 443. 

A better way is to block port 80 from your firewall. This way, no one from the Internet will be able to connect to port 80, but you will have access from the LAN in case there is a problem with HTTPS.