Right, after digging, and for everyones future reference I have found a solution, as this appears to be a bug. The link to the thread is :- https://www.daz3d.com/forums/discussion/339441/mrl-dforce-long-hair-not-showing-up-in-render

and if you don't want to read through that, just do this snipped from the site... "I found it. In the Scene tab under the MRL DFLHair Base - HDE (Hair Parented to this) you will find MRL DF Long Hair. In the scene tab - click on the MRL DF Long Hair. When you go to the Parameters tab/All and activate "Preview PR Hairs" and increase the "Viewport Line Tessellation Sides" and "Render Line Tessellation Sides" the hair appears in the Iray preview render mode." I only increased the last two by one, and then the hair shows up in the iray and delight renders. Hope this helps someone as it is one annoying bug.

Getting old and still making "art" without soiling myself, now that's success.