Unreal won't launch when my Vive is disconnected - anyone experience this issue ?

Hi - since I disconnected my Vive from my PC I am no longer able to open ANY projects in Unreal. I can’t even open a blank template to try and disable the VR plugin.
Unreal launches and gets to 83% but then it seems to make steamVR open automatically and this seems to cause the stalling issue seeing as STEAMVR can’t locate the hardware. I’ve gone into the developer settings of steamVR and disabled ‘Start steamVR when an application starts’ - this has made no difference.#
I don’t have the headset with me this week so plugging it in is not an option! Any advice ?