These properties have been used previously to model the electronic structure of SCPs, and one can find detailed descriptions elsewhere (key details are repeated in section 4 of the SI which also gives further information on the sampling procedure) . One of the principal findings of our study (Figure ) is the near independence in calculation of bulk properties with varying polymer chain length if equivalent sampling is achieved that is to say that longer chain lengths are not necessary to accurately model the electronic structure of the bulk. We find that the properties calculated with our approach match closely with those from experiment: the DOS-derived optical band gap here is 1.60 eV compared to 1.56 eV determined experimentally . It is also interesting to note that the valence band here is ~0.2 eV broader than one obtained from conformations of isolated chains, highlighting the importance of including a realistic description of the environment when computing this key quantity . Upon calculation of transfer integrals between HOMOs localised on BT fragments at crossing points (Figure ), a sizeable minority of couplings are larger than |0.1| eV which, in conjunction with non-negligible contribution from BT to the DOS at the bandedge (~20%) in Figure , confirms the hypothesis that interchain transport is mediated by BT-BT interactions, as already proposed in refs. .