I made sure to install propertly but doesnt appear in the Node menu of Shader Editor - although I can see Voronoi Scatter & Un-scatter as greyed out options when I right clic, can you help?
The Node menu is pretty long, so it may just be that you need to scroll to the end? Since it's not super convenient I like to add it to my quick favorites by right clicking on it in the menu, so that way it appears in my Q menu.
Using it via the right click context menu will not give you the popup with the options (I think it's a Blender limitation) and it will resort to using the defaults.
If Voronoi Scatter is greyed out then you just need to select some image textures first. If Un-Scatter is greyed out then you just need to select a scatter node once one has been created.
Hope that helps!