No Oculus output in Unity

I've been through the OculusUnityIntegrationGuide with a fine tooth comb.
I've tried adding the OculusPlugin.dll to the Unity\Editor folder.
I've tried adding -force-d3d11 to a shortcut to the _DirectToRift.exe build.
I get no build errors.

So far when I hit play I get the stereo output on my computer screen and nothing on the rift.
When I build it I get nothing but black and no rift activity (amber light), same with _DirectToRift.
Demos work fine.

Does anyone have suggestions bearing in mind that it's possible a simple oversight has been made?

Thanks,
Eric