Microsoft 365 stealth upgrades

[nzoomed]

Yes that account is still there, I did remove it earlier to see if it made any difference, but doesnt change anything.

i think that area is where ms store any of the accounts that can be used 'everywhere', so you would need to remove it from there, as well as sign it out from Outlook. 

But it would seem that the account with the H&S license is being used on the device somewhere if it finds its way back into that settings-accounts list.  

I guess the only option is to keep using that 'Switch License' button...

Yes, I had given that a go and it got me to sign back into the microsoft account, then upon restarting outlook, it would ask me to sign back in again, im guessing something is broken in the registry and/or the other licence saved there somewhere.

as a workaround you might be able to leave them a batch file on the desktop to deregister the errant license key, which should default back to the 365 license

some info here about that
https://support.microsoft.com/en-us/offi...mmand_line

looks reasonably straightforward

I had given this a go yesterday and it came back and said no licence key found, this doesnt appear to be an issue with a licence key saved in the system, but rather linking the licence from the other microsoft account.
In the meantime, I reinstalled and activated office, then disabled automatic updates for the time being, seems to have solved it for now until i can find a more permanent fix.
There is probably some script out there that can clear every remnant of microsoft office installations, but my main concern is seeing the licence show under the windows user account settings, windows has gotten this information from the microsoft account when it was signed into it some time prior, but despite being switched to a local account, this licence still is visible here, even after removing the microsoft account in credential manager.