Stellar population modelling of the CSS, using independent codes pPXF (left column) and Prospector (right column). The top row shows SED fitting to the photometry, the middle row shows full spectral fitting where the spectra are normalised by the median flux, and the bottom row shows the inferred non-parametric star formation rate vs time. Qualitatively, both codes produce remarkably consistent results, with a very extended SFH that finished with a strong burst ∼1 Gyr ago.