how to Invert Oculus OVRCameraRig in Unity????

try setting the localScale of the LeftEyeAnchor and RightEyeAnchor to (1, -1, 1)

thanks for your reply PhyterJet,
Below is the code in my UpdateAnchors Method, unfortunately it isnt working, any other ideas or am i doing something wrong?

Thanks
:)

private void UpdateAnchors()
{
OVRPose leftEye = OVRManager.display.GetEyePose(OVREye.Left);
OVRPose rightEye = OVRManager.display.GetEyePose(OVREye.Right);

leftEyeAnchor.localRotation = leftEye.orientation;
centerEyeAnchor.localRotation = leftEye.orientation; // using left eye for now
rightEyeAnchor.localRotation = rightEye.orientation;

leftEyeAnchor.localPosition = leftEye.position;
centerEyeAnchor.localPosition = 0.5f * (leftEye.position + rightEye.position);
rightEyeAnchor.localPosition = rightEye.position;
rightEyeAnchor.localScale = new Vector3 (1, -1, 1);
leftEyeAnchor.localScale = new Vector3 (1, -1, 1);
}

I'm sorry but I was wrong, the scale does not affect the cameras viewport.

As I learned in this thread https://forums.oculus.com/viewtopic.php?f=37&t=22522: as of the 0.5.0 Unity Integration we are advised not change the transform of the "anchor" gameObjects (which are leftEyeAnchor, rightEyeAnchor, CenterEyeAnchor and TrackerAnchor).

So instead we modify the new parent gameObject: 'TrackingSpace'

This update method rotates the attached gameObject by 180 degrees when the the A key is pressed. So add this to a script attached to the TrackingSpace object and see if it does what you want.

bool rotated = false;
void Update () {
   float z_rotation;
   if (Input.GetKeyDown (KeyCode.A)) {
      if (rotated)
         z_rotation = Mathf.PI; // 180 degrees
      else
         z_rotation = 0; // 0 degrees

      transform.rotation = Quaternion.EulerAngles (0, 0, z_rotation);
      rotated= !rotated;
   }
}

EDIT:
If you want to 'flip' the cameras vertically (and not rotate) then you can use this script. Which should be attached to both cameras 'leftEyeAnchor' and 'rightEyeAnchor'.

using UnityEngine;
using System.Collections;

public class FlipCamera : MonoBehaviour {
    void OnPreCull () {
        camera.ResetWorldToCameraMatrix ();
        camera.ResetProjectionMatrix ();
        camera.projectionMatrix = camera.projectionMatrix * Matrix4x4.Scale (new Vector3 (1, -1, 1));
    }
    void OnPreRender () {
        GL.SetRevertBackfacing (true);
    }
    void OnPostRender () {
        GL.SetRevertBackfacing (false);
    }
}

You're a Saint, it worked!! thanks for the help really appreciate it :D