[VIVE] Low FPS on Packaged project


I have a very detailed scene created over top of the 4.13 VR template and the final package project is seriously tanking on the vive, I tried many ways of optimizing the scene, I have a shed load of SM’s that I’ve now instanced in the scene, even reduced the texture sizes and hardly used any PP settings, The project is a ArchViz scene so I am going for realistic look with a few intractable objects.

Anyone any ideas where I can look to see what is tanking and what else I could do I?