Hi Samb,
I’m in line with darthviper’s thinking on this one. You need to adjust the Lightmap Coordinate Index to the correct channel.
From the images you’ve provided you show the build settings where you are using your source and destination lightmap coordinate as UV Channel 1. In that same picture you can see that the lightmap resolution is set to 64 under the Static Mesh Settings, but we cannot see what your Lightmap Coordinate Index is set to under the advanced roll-out.
In another image you’ve shown the UV Channel 1 layout, but this does not show where it is assigned to.
The Lightmap Coordinate Index should be set to 1 since this appears to be the UV channel that you would like to use.
Also, it’s key to know that the build settings are just that. They are a way of generating or “building” your settings for your Static Mesh, but they will not set them up automatically.