Simple light baking problem

Have been fine with this in tutorials but struggling with my own scene with imported meshes. At it's most basic, I want to bake this orange static light so that when I delete the light it's still there baked into the wall texture.

- Have set the resolution to the room as 256
- UV2 is selected as LM and have created a perfect light map with padding etc
- Simple white vector plugged into diffuse as a material

Any ideas?