So tried NetFxRepairTool again and seemed to work. It allowed me to install NDP48-x86-x64-AllOS-ENU.
I then restarted and tried updating again. This time it had "2020-02 Cumulative Update for Windows 10 Version 1803 for x64-based Systems (KB4537762) - Error 0x80070002". I downloaded and manually installed the Win 10 Servicing stack update. It seemed to take.
Tried the update again after a restart and now says I am missing "Windows 10, version 1903" So I am in the middle of trying that update.
Seems to be heading in the right direction..... hopefully.