It does work nicely, but there are a few things to help people:
If you do 'make release' it will install two new zip files in the releases directory.
I just cd there, unzip the relevant arch (in my case x86_64), and then run the install file.
If you get a format exec error (journalctl --user --unit gnome-dav-shim.service) simply replace the 'working' binary from this unzip in the proper area.
It does work nicely, but there are a few things to help people:
Thanks for a GREAT program!