Wheres the light coming from?

Hi, Im new here and new to Unreal.
Im trying to track down this light source in my scene. It appears to be a default light source thats not obeying any light casting.
Ive searched the forums and tried:
adding a light (suggested it would automatically turn off any default lighting
Ive deleted post process and tried without any exponential height fog.
and tried baking lighting with different setting as well as searching thru the worldsetting for any ambient light options
In the image I have turned off all lighting in the scene as well and fog and particle systems, and selected Lighting Only.

Im sure this must be a simple solution but I havent read or seen any info on it. Id like to just be able to start with a completely black/lightless viewport is this possible?
Thanks in advance