Hey Makigirl,
Thanks for the help, both good ideas. Unfortunately it is still the same after the build. I have upped the lightmap resolution to 2048 in both the lightmass settings and the build settings as I believe that is the only way to change padding in UE4 generated lightmap UV’s? I also ticked the 2-sided material option for the material but still no luck. Any other suggestions would be very welcome.