So my hosting has very kindly installed lxml for Python 2.7 for me.
That fixed my problem of having a mismatched version error and the error with no tree builder found.
There is however, still an error with my BlogPageIndex having an AttributeError that only shows up as ‘cannot save draft due to errors’ on my Wagtail interface.
also had the embarrassment of pronouncing Django wrong in a conversation. That quite possibly caused me Internal System Error with missing module ‘shy’.