Quote - The ghosty bit looks like the underlying mesh is being highlighted somehow. Anyone have an idea how to get rid of this?

Looks like specular or reflection (see my earlier posts in this thread, I mention exactly this problem in 2 posts) - make sure you have nothing in those channels for all the hair materials (you might have removed specular for the outer layers but not an inner layer, if they are different materials).

Which hair prop is this? I don't think I have it, but I'll try it if I have it.