Exactly what I was after - thanks! I think it bust as my home still has cruft on it from when I was trialing nemo months ago - nemo isn’t in my build since I switched my distro.
I am slowly merging my old config data and the default profile config data to get my Manjaro install working properly but without losing any of my previous stuff.
My issue recurred later after installing Visual Studio code with just the first command. I’m now editing the file directly and making sure that Nautilus is the first option in that list. Hopefully it’ll `stick’ now.