Top-left panel: Colour magnitude diagram in the V vs B − V plane of the photometric data of the HB stars in NGC 2808 from Momany et al. (2004). The Na-Poor and Na-Rich populations from Marino et al. (2014) are represented with filled and open points, respectively. The red and teal contours and points represent the best fit simulations for the 1G and the 2G1 in this cluster, respectively, together with a sample realisation. Bottom-left panel: Histograms of the colour distribution of the stars belonging to the two populations in the data and in the best fit simulations. The histograms of the simulated stars are normalised to the same number of stars we see in the observed sample. Top-right panel: Same as the top left panel, but for the U vs U − V CMD. Bottom-right panel: Contour plot of the best fit simulation for the 1G and 2G1 populations compared with the m_F606W vs m_F438W − m_F606W CMD for the HST photometric catalogue.