Even with reduced face-face interaction strength, bringing them outside the range of typical OSCs, most of these systems did not remain isotropic in the bulk. The two that did were the least anisotropic in shape and are the face-on outliers at ∆ Ū -T ∆ S ≈ 2ε in Fig. . While this result shows that it is possible to achieve a slight face-on orientation at the vapour interface for anisotropic particles while still maintaining an isotropic bulk phase, these points do not fall in the region where the simple free-energy predictor presented here predicts a face-on orientation. The deviation from universal scaling at the vapour interface is likely due to several factors. Firstly, for a number of the systems, particularly those at high density, the pressure, measured as the normal force on the substrate, was relatively high -up to 1200ε/σ 3 in some cases. Examining the dependence of the relationship between s vap and the free energy on system pressure (ESI, Fig. ) shows more extreme side-on orientation (lower values of s vap ) at higher pressures for the same value of the free energy. While the orientation at the solid interface also shows a slight pressure dependence (ESI, Fig. ), the effect at the vapour interface is more pronounced. As the vapour interface is constrained by a repulsive harmonic wall, interacting with the centers of each fluid particle, high pressures correspond to a strong interaction between the fluid particles and this wall, artificially suppressing fluctuations and in some cases (e.g. ESI, Fig. ) resulting in a density enhancement relative to the bulk and oscillations in the density profile that are not representative of a true vapour interface.