Found a fix...
https://forums.stardock.com/486022/start10-support-faq#reinstalling
Just for context
Upgraded from Win10 Pro to Win11 Pro via Windows Update in September via Insider program
Start 10 was installed during upgrade, Windows Upgrade Advisor warned I needed to upgrade to Start 11 beta.
Stopped Windows Upgrade, rebooted
Installed Start 11 Beta
Rebooted
Upgraded from Win10 Pro to Win11 Pro via Windows Update
Didn't use Start 11 in the first couple of weeks to get used to Win11 start menu.
Tried Start 11 yesterday..."Problem found"
Ran script in link
rebooted
reinstalled Start 11 0.55
rebooted
Now the toggle 'does something' -------->Success
