Atomistic quantum mechanical modelling has played a critical role in driving many of the advances made involving crystalline materials over the last two decades -originally in terms of rationalizing materials properties, but now increasingly in predicting and optimizing both materials and devices . A significant challenge, however, lies in applying the same quantum mechanical methods to amorphous materials , despite their increasing role in devices; these include dielectric layers in organic electronics, and as protective coatings across a range of materials . The challenge lies in capturing both the complexity of the local structure and the heterogeneity and structural variations that occur over a variety of length-scales. Amorphous structures lack the translational and point group symmetries present in crystalline materials, which enable calculations of increasingly large cells. It is also non-trivial to validate such a model against relevant experimental structural data, as symmetry allows structure solution from X-ray diffraction (XRD) experiments, while structure solution of amorphous materials relies on techniques such as Nuclear Magnetic Resonance (NMR) and X-ray Absorption Spectroscopy (XAS) to infer local structure. To understand and ultimately improve the electronic properties of an amorphous material, it is imperative to produce an accurate model of local atomic and electronic structure.