Thank you
Yes it is assigned to the correct lightmap UV channel.
solving this issue inside Unreal is like a myth, no one talks about it. It’s strange that it is pretty common but navigating it is a mystery as Epic has pretty much made Unreal self explanatory.
I’ll have to mess around with the UV section in modeling tab to see if there;s anything more can be done. I’d MUCH rather avoid exporting assets to 3ds then reimporting back one by one.