Grouped texture parameters not showing
When I select a grouped texture in the tree for example if I select Arms or Arms/Base nothing shows in the parameters window, but if I select an individual element like Mixing, Thin Film or Bump I see the parameters.

Comments
Do you have Show Sub Items checked at bottom-left of the Surfaces pane?
That was it, thankyou. Probably the most obvious thing to notice now that I'm looking at it.
Question is, how did it become un-checked?
Perhaps a mis-click, I don't think there is a keyboard shortcut for it.