The update of the Roon Web Controller provided by @Mike_Plugge gave me a good opportunity to test the update function of the extension manager in a real life situation.
I performed the update via the Actions pull down menu within the manager settings. The update went fine and when at completion the extension restarted, it identified itself as version 1.2.0. The only additional action I had to take is to re-authorize the web controller due to the additional Roon APIs that it now uses.
So I’m pretty happy, a nice and up to date web controller without the need to fall back to the command line 