Funnily enough, while following your advice to use a temp environment I found another thread which discusses many of the same issues.
Whatever went wrong specifically yesterday in the workshop, it does seem that I’m generally not using Julia the best way.
Thanks again for all your help, I shall try out these suggestions, this definitely feels like the “secret” I was missing when I couldn’t understand why I was running into these issues. In hindsight I probably should have posted to the newbies thread.