For a bulk nematic GB fluid, the orientation at the vapour interface has previously been shown to scale with the ratio of the shape and interaction anisotropy parameters, κ/κ , with a faceon orientation observed for κ/κ < 1, and an side-on orientation otherwise. For the systems studied in this work, in which the bulk phase is isotropic rather than nematic and in which solid interfaces are also considered, Fig. shows that κ/κ is not a good predictor of orientation at either the solid or vapour interface. At the vapour interface, the orientation does not appear to depend on κ/κ for κ/κ > 1, although there seems to be a transition to very marginally face-on orientations at κ/κ < 1, as predicted previously for bulk nematic fluids. The systems that display a slightly face-on orientation are those with the most isotropic interactions studied here (κ = 0.7), resulting in very slight orientation preference, while those with the more face-on orientation are where side-side interactions are stronger than face-face (κ = 1.2). Stronger alignment could be achieved by decreasing κ (increasing interaction anisotropy), but the corresponding increase in the shape anisotropy κ required to maintain κ/κ < 1, coupled with the more anisotropic interactions, would likely result in systems that are anisotropic in the bulk. At the solid interface, there is a weak trend towards a more face-on orientation as κ/κ decreases within each set of substrate/temperature conditions, but there is a strong dependence on temperature and κ/κ = 1 does not correspond to the transition from side-on to face-on orientation. This dependence on temperature points to a significant entropic contribution, which is only accounted for implicitly in the κ/κ parameter through the shape anisotropy κ.