Help HP ZVR Virtual Reality Display

[MaxPalmer]

I've managed to pick up an HP ZVR Virtual Reality Display (for free!), but can't get it to output 3D / Stereoscopic content. Anyone still using these in 2021 who knows how to get it to work?
Is this a Windows 10 Version Issue?
Is this NVidia driver issue - I rolled back to the last supported 3D Vision Driver and have enabled 3D for the display.
I've tried building 3D content in Unity with the ZSpace SDK, no joy.
There is some suggestion that on a 1080 (and other consumer cards) that 3D content will only work in full screen mode. Is that right? Is there any content I could test?

At the moment it feels like a paperweight - the tech is cool, the stylus works and it tracks my head position when wearing the glasses, but alas no 3D.