The dead simplest lower the bar, move the bar, trip over the bar, pyugri...

...d/iris integration. See https://github.com/pyugrid/pyugrid/issues/32. Thanks to @ChrisBarker-NOAA , @rsignell-usgs, @benjwadams, and especially @rhattersley. Enjoy.
As mentioned by @ChrisBarker-NOAA, this path needs to change to `('NetCDF', 'ugrid')`.