Firstly, I'm new here (and a newb with P7, and loving it!!!).

This is a render of Teagan and if you look carefully you can see the makeup of pologons in the shadow areas. I've read loads and loads (getting confused now) and have set up IBL (light probe) and AO on this light. I've added SSS to the skin. I feel I'm going round and round in circles attempting photo realism. 

Any advice on the pologon issue or anythin relating to photo realism would be gratefully received.

Rob

Try setting the minimum shading rate in the render settings to a lower number than the default. I usually use .08 (click the number and enter the digits, the slider for me doesn't offer good fine control over lower numbers).

Looks like you have a few issues there.

Firstly, I don't think the Fastscatter node is that great for skin - it's more suited to waxy objects.  Also, looks like you have AO switched on for the main light - I suggest using the AO nodes in the material room rather than light based AO (light based AO doesn't give great results on faces, since the nose and other features cause too much shadowing).  If your whole scene is lit by an IBL light, you wont getting any specular - so you need to use some normal lights too to give your render some depth.

Photo realism starts with using great texturemaps and bump maps.  Then you need perfect shadows, a realistic face shape, and skin materials that handle light in a similar way to real skin.  On a portrait, if you don't get the eyes right, your render won't be convincing.

Check the tutorials in my sig below - will explain how to do some of those things.

Thanks very much for this. So you'd suggest that I use the AO nodes in the material room and remove the AO on the light. Also add some specular (via spot lights?). Great stuff, I'll pop along and check out your tuts.

Rob