Done some more testing.

With the LightWave Normal export, when I bring the LWO into LightWave the entire Vertex Normal map needs flipping on all axis to look and render correctly.

With the modo Normal export, when I bring the LWO into LightWave the Z axis on the Vertex Normal map needs flipping to look and render correctly.

So, as it stands, none of the options import pefectly without some extra work in LightWave.

Regards
Matt