Absolute position of Tracking Camera in Unreal Engine

Hi, to get the absolute position of the tracking camera in Unreal I was previously using ovr_GetTrackerPose and then subtracting that from the base position using Settings->BaseOrientation / Settings->BaseOffset.

Since 4.17 the plugin has moved from LibOVR to the condensed OVRPlugin and the functions I was using have now disappeared and I can't see a direct replacement (although I may have missed something obvious!)

What is the best practice way now of getting the true camera position relative to the HMD which would allow a box to be drawn where the tracking camera is in the virtual space as in the OculusRoomTiny CameraVolume example from the SDK.

Huge thanks!
Ally