Thanks for the reply Karthik.
I posed the question because the following section in the Vserver Administrator Capabilities Overview Guide seems to indicate possible control via HTTP(S) and I wanted to ensure I wasn't missing any required configuration to enable this:
Access methods for user accounts
Depending on how the cluster administrator sets up your user account, you can access a Vserver for
administration by using certain access methods.
You can access a Vserver by using the following access methods:
• SSH
• Data ONTAP APIs
• HTTP and HTTPS
I will instruct our Vserver administrators to use SSH for now.