After a great deal of running around I managed to figure out that I was missing an additional PATH entry, both of these were required to get eb to run on windows:

%USERPROFILE%\AppData\Local\Programs\Python\Python36\Scripts
%USERPROFILE%\AppData\Roaming\Python\Python36\Scripts

NOTE: If you have Python 3.7 installed, change "Python36" to "Python37" in both of the path…