Oh poo! That is not good. But I probably should have thought of it. That's the problem with node.js and Node-RED, there are multiple locations things can be installed and npm has no robust way of finding things no matter where they are installed, you kind of have to know at least some things. A right pain!
It would be interesting to see if Node-RED was happy with things installed there though - I think it would be. It is a pain in the butt to have things effectively installed globally which is what the instructions are doing.
Well, OK, thanks for the info. At least we know that things still work when installed that way. It is just a warning message really anyway so I can make some simple ammendments to it.