Although the consideration of only nearest-neighbour interactions in the calculation of the interfacial energy difference is a major simplification, it accounts for the most significant inter-particle interactions due to the rapid decay of interaction strength with inter-particle separation; for example, next-nearest-neighbour interactions are only a few percent of the nearest-neighbour interactions in the face-face orientation for the systems studied. Thus, even though a more complex description of interfacial energetics that includes more inter-particle interactions may be more quantitatively accurate, it is not expected to qualitatively affect our findings.