Can't install Office as another version is already installed. Except it's been uninstalled!

I have a laptop which out of the box had 5 different office installations (5 different languages) pre-installed. I removed each through Add/Remove programs and rebooted. I am now trying to install using my setup.exe and configuration.xml I downloaded to install my Office365 versions of Office (this install works on other computers). When try to install I get a message from the Office installer stating that: We can't Install The following product(s) can't be installed at the same time: ProPlusRetail I tried running the Office uninstaller from this troubleshooting web page: Troubleshoot installing Office 365, Office 2016, and Office 2013 I still got the same error above! I have tried removing Office registry entries (from the Software Key (inc SysWow64 subkey), the Microsoft Office directories from Program Files and Program Files (x86), cleared out anything Office related in ProgramData. To no avail! Every time I try to install Office365 I get the above error.  I tried downloading the ProPlusRetail ISO and installing, rebooting, running Word setting it up and then rebooting and uninstalling the ProPlusRetail version, reboot and try installing Office365 again, and yet again it fails with the error as above. Despite being uninstalled, it still thinks a version of Office is installed? What can I do, I assume it must be leaving some Registry entry somewhere or some files, which are likely causing the issue. Please Help!