Mean values of [Fe/H], [O/Fe] and stellar age of all the galaxies in the sample, ordered by galaxy. Each dot indicates the value of an observable for a given galaxy, colour-coded by component, while the dashed vertical lines shows the average over the sample. Shaded areas indicate the ±1σ region. We note that the solid lines that join the data points are included for visualisation purposes but lack any intrinsic meaning.