Broken Metahuman physics asset

So I’ve been playing with the physics asset tool/editor and trying to set up a complex collision hull for my MH… but as I’ve moved through the skeleton trying to create various physics volumes, various bones have disappered from the skeleton tree on the left. Now… I have a metahuman with just hands feet and pelvis!

How do i get those bones back? Or… how do I get a brand new physics template for my MH?! Because, looking under common>common>male>med>body… etc etc… all I have is the physics file I just buggered up! How do I get a new one?

Many thanks…