Duplicate versions of nbextensions - how to know which one to delete

I want to install nbextensions for my juypter notebooks. Having followed the instructions from here, I can see the nbextensions dashboard.

However when I go to enable this I get the following error:
"This nbextension's require url (splitcell/splitcell) is referenced by two different yaml files on the server. This probably means that there are two installations of the same nbextension in different directories on the server. If they are different, only one will be loaded by the notebook, and this may prevent configuration from working correctly. Check the jupyter notebook server log for the paths of the relevant yaml files."

I find that I indeed have multiple entries....

This link suggests to delete one (though there are actually 3)... what I don't know is which... I don't want to delete something that then breaks my jupyter instances completely.

I have the feeling that I am not using the instance under anaconda. What do I damage if I delete this?

Appreciate any insights, and let me know if you need more information,
J

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.