Attempting to run vncserver as non-root user gives me this error:
couldn't find "xauth" on your PATH
So I do a search for xauth:
find / -name xauth
which finds it in /usr/X11/bin
Also, knowing that when logged on as root I don't get this problem, I assume that root must have this in its path so I log on as root and run:
This confirms that /usr/X11/bin is in the root users path.
I Log out of root session and add xauth to path:
PATH=$PATH:/usr/X11/bin && export PATH
vncserver now runs successfully but with some errors referring to permissions on the ~./vnc & ~./Xauthority folders.
For some reason root:root is owner of the .vnc in my root folder, presumably because I had run vncserver initially while su'ed from my non-root users session...
pfexec -R marc:staff ~/.vncpfexec -R marc:staff ~/.Xauthority
Sorts that out!
vncserver -kill :1vncserver
and all is working great!