@Andrew2015 Thanks! The last two answers you gave fixed both my problems 
(the second one I had not posted about yet)
The issue I raised up in this thread was solved by one of the answers to this:
https://forums.unrealengine.com/showthread.php?98-Cannot-open-include-file-windows-h
(specifically “In visual studio go to project properties - > vc++ directiories and set include and library , library winrt, reference too i think directories to inherit from parent.”, Cube222)
However as this was a Win 8.1 laptop upgraded to Win10 I expected SDK 8.1 to already be present on the machine. It was not. After installing it it solved another problem I was having which was actually running the “GenerateProjectFiles.bat” from the repository as it was not finding an installation of VS2015. With SDK 8.1 it all worked.