Firstly, thanks to Michael Balzer for fixing my errors in the rst files I checked in. (Also, apparently I can't spell Auxiliary - doh). I _had_ tried to get sphinx working recently and failed miserably, so I tried again this morning.

The problem is that ubuntu:

* Doesn't provide a package for m2r2 or sphinx-mdinclude (a fork of m2r2)

* No longer allows you to pip install into the main python library path

So first I got rid of the installed sphinx-doc

sudo apt remove sphinx-doc

Then I set up a sphinx virtual environment

pipx install sphinx
pipx inject sphinx sphinx_rtd_theme docutils mistune requests sphinx-mdinclude

For some reason I was getting run-time python errors with m2r2 which is why I tried switching to mdinclude.

In docs/source/conf.py I changed

extensions = [ 'm2r2' ]

to be 'sphinx_mdinclude' instead of 'm2r2'

The pipx command creates a virtual execution environment for sphinx and puts a shim for sphinx in your local path that runs it in the virtual environment.

//.ichael