Thanks electroglyph
The procedurals I understand though the jpeg is different (or not so clear)
The dark smudges of which you talk are part of the diffusion map.

I'm trying to get 3 different specular levels on 3 different surfaces (green case= none, thumblock= some, metal=full ) and its nearly there. Those greyscales values need to be via the spec halo for this to work.
So contrary to my original post I now don't know what part specularity plays in this