Why can't I rename my MIDI Bus in Audio MIDI setup on Mac mini?

I am having problems with setting up an IAC driver in Audio Midi Settings/Midi Studio. I want to add a bus and name it. 'Device is online' is checked. Adding a new bus is OK, but when I fill in the Device Name field and click Apply, this does not show on the ports (it just retains the name 'Bus 1'. ) Double clicking on 'Bus 1' does nothing, contrary to the Apple instructions which say you can rename it this way. If I add further buses, with different names in the Device Name field, these will all show up in the connected midi device with the last used name in the 'Device Name' field.

Is this a permissions problem?

I'm running Ventura 13.7 on an M1 MacMini.

Any suggestions most gratefully received!

[Re-Titled by Moderator]