Spherical gravity with OVRPlayerController

This is my first forum question, please let me know if it is in the wrong place etc!

I have a unity project in which the player can walk around a sphere, the tutorial I followed/demo is https://www.youtube.com/watch?v=TicipSVT-T8 with the three scripts here: https://github.com/SebLague/Spherical-Gravity

Everything works beautifully when using FirstPersonController.cs from the above repo however when I disable FirstPersonController.cs and instead use the prefab OVRPlayerController asset (provided in Oculus Utilities for Unity 5) there is a conflict causing the VR camera to rotate uncontrollably. I have spent many hours trying to resolve this but I am not yet skilled enough to overcome the issue. I think its the OVRPlayerController rotating the camera and the GravityAttractor.cs script rotating to align the bodies up axis with the centre of planet. It's a long shot to come here but I really have spent hours researching and I just don't yet know enough about Unity to resolve this by myself. Could anyone give me some pointers? Why would the scripts from SebLagues github repo work fine on a primitive cube and then turn into chaos when applied to the off the shelf OVRPlayerController?

Is there a place I can upload my project for others to view in order to help my learning?

Thank you all in advance.