Quote - Also check if "Visible in Raytracing" is on for the hair in the object's Properties panel. This is not a material setting, but an object setting. It might be off.

 

It wasn't checked!  I've checked it and will try another render.  Hopefully that and unchecking "lit_mlt" will do the job :)

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi