Thanks for the quick reply but alas that doesn't work, that seems to break the objects up into lots of individual poly objects ballooning the scene size, and also quite a few of them, all individuals. They are set to match the forest item display parameters which as you can see in my attached image thins them out quite a lot!!
Maybe I need to do an uninstall / reinstall and put them all to the shared directory option?
Also I am now getting the vertical wall presets not rendering, also doing this randomly, it's rendering the vines but no ferns, I'm guessing re-installs needed. No point wasting more time.
I'll try using the shared directory structure this time.
I've rendered many times before with forest pack with none of these issues.
Thanks again.