They are 3D meshes, imported as OBJ files and the turned into symbols.
I have actually solved the problem via VSS support. It seems that sometimes VW can process OBJs differently (or they are created differently at source). In the above the mesh faces are reversed so what you are seeing is effectively the inside of the back of the figure.
I passed the OBJ through cinema 4D and re-imported it to VW and the problem is resolved. On the left is the new symbol.
I've posted this solution in case anyone else comes across similar behaviour