In all structure optimisations reported in this article, only the positions of the adsorbed organic contaminants were optimised, and the zeolite structures were held fixed. It is clear that local relaxations of the zeolite framework upon guest molecule adsorption should be taken into account in a comprehensive DFT treatment. In the context of the present work, however, it was deemed preferable to restrict the comparison to host-guest interaction energies and (for selected cases) the positions of adsorbed molecules. Including a relaxation of the zeolite framework would add an additional layer of complexity, especially as a considerable dependence of the optimised structural parameters on the chosen DFT approach has been observed in comparative studies of guest-free zeolites. Several prior benchmarking studies of host-guest interactions in zeolites kept the atomic coordinates of the framework atoms fixed. Because CCSD(T) calculations are not feasible for periodic structures, cluster models representing the most significant part of the zeolite framework were employed in Part 3. These cluster models were extracted from the adsorption complexes optimised with the PBE-D3 functional, considering two different configurations for MOR and one for FAU. The closest part of the zeolite framework was cut out from the periodic structure, resulting in MOR models with 19 T atoms and a FAU model with 18 T atoms. Dangling oxygen atoms were replaced by hydrogen atoms, fixing all Si-H distances to 1.48 Å.