Hello ianmoran1970,
I tested this in 4.10.1 and I was able to reproduce this issue on our end. I was able to use the VR mode in standalone as long as I have not used the VR preview. I have written up a report (UE-24264) and I have submitted it to the developers for further consideration. I will provide updates with any pertinent information as it becomes available. Thank you for your time and information.
Make it a great day