thanks mate!, thats the one!.
Exact problem mentioned in the posts. Rec lights not appearing in translucent materials, this fixed it all.
Its an understandable problem as many realtime engines dont support rec lights in reflections including alot of viewports in modelling apps. So yeah, I get that it is default ticked off for optimization, But jeez. If you didnt mention it, I would of assumed forever more that it was just a limitation of unreal.
Legend, Don’t know how you found that little nugget of gold