For the record in case this helps anyone else - I was able to change the login from Azure Bastion to use the intended “RhinoComputeUser” created in the bootstrap script as follows:
Azure portal > VM > Reset Password > … then simply add the RhinoComputeUser creds.
This kept both my original Admin account and the RhinoComputerUser account but made both work for logging in.
I could then point IIS > RhinoCompute > BasicSettings > Connect As… to the RhinoComputerUser creds so that from now on the installation is inline with the standard set up created by the script. Which means I can test for missing grasshopper plugins by logging in with that account and opening the grasshopper scripts and clicking download & install for any that are missing.
