Here's my update after installing a fresh windows image on another harddrive...still the same. There is some fundamental incompatibility between my laptop and the PiMax 4K, Which is weird IMO.
I wonder if the HDMI port is struggling to provide enough power? it says HDMI is connected but the LED is green which is a HDMI connection issue. I wonder whether it's worth trying a powered HDMI splitter or something. I'm really grasping at straws now.
Honestly I'm really disappointed, the headset is awesome and to be honest after seeing it in action first hand I don't think I could settle for a lower resolution screen. I think my only option at this point would be to get an external GPU but that seems like a lot of expense to get a VR headset working.