Integrated optical and near-IR colours as a function of age for Z = 0.008, as obtained in this paper (open squares – results for MC simulations with 1000 AGB stars; notice the overlap of the symbols in the upper two panels, due to low magnitude fluctuations that mimic solid squares), Paper I (dotted line), BaSTI (dashed line), Marigo et al. (2008) and Maraston (2005) (solid and dot-dashed, respectively) population synthesis models (see text for details).