Further to the LightingTest2 sample, I’ve dug deeper and think I may have found the root cause of this. When I took my test texture off the object the lighting worked. I realised this is still using a UE default material and spent some time looking at the material we have.
It turns out that the Material Blend mode set to Transparent or Additive causes this issue. When set to Opaque or masked the lighting works as expected.
So now the question begs, is there a way around this?
Thanks, Josh