OK, so the equivalent of "Hello world" has just started working here. I typed in all the gubbins included in the tutorial document which implements a 4-bit counter displaying itself on the LEDs. Finding and fixing the typos from the Quartus error messages was informative.
with the single line:
SUBSYSTEM=="usb", ATTRS{idVendor}=="09fb", ATTRS{idProduct}=="6001|6002|6003", OWNER="root", GROUP="root", MODE="0666", SYMLINK+="usbblaster"
Typing that in and restarting jtagd failed to improve things. Removing and unplugging the DE0-Nano was all that was then required.
Hope this helps other Linux users.