It is worth emphasising that DFT optimisations starting from symmetric structures did not reveal the majority of local distortions, which became apparent only in the AIMD simulations. Except in the case of GeO2-AST_QNU, the undistorted structures are local minima, and the optimisations will not leave these local minima. This highlights that it is advisable to either employ AIMD simulations, or -if these are not feasible -to generate a set of perturbed starting structures prior to the DFT optimisations in cases where local distortions are expected.