Can't uninstall Microsoft Office?

I recently found I was still using the 32-bit version of Office. I tried to download Office 64-bit but it would not install, it told me I must first remove/uninstall the existing Office 32-bit. Fine I thought, I went to Settings | Apps | Installed Apps. I found Microsoft Office in my list and uninstalled it. When I tried the Office 64-bit installer again, it still complained Office 32-bit was still installed. 

Solution

I downloaded a special Microsoft app called 'Microsoft Support and Recovery Assistant'. You can find it here: https://support.microsoft.com/en-us/office/uninstall-office-from-a-pc-9dd49b83-264a-477a-8fcc-2fdf5dbf61d8

Install and run that application, it will take some time but eventually it does cleanly remove the existing Office installation from the computer.