In the meantime I took the risk and deleted the version in the --user level.
jupyter contrib nbextensions uninstall --user
Honestly I have no clue as to if that's the right way to have gone, but it seemed to have worked.
Running jupyter nbextension list still gives me the same answer as before but now the extensions work (after restarting the instance).
Whilst I do have a couple of different environments installed in conda, I did this as an experiement and only one is actively used. I tend to launch my jupyter notebooks from shell and the base environment, and then create and work in a different environment as that is where I have installed all my packages.
I'm happy to be told I'm making a pigs ear of this if someone can tell me how I should be doing this.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…