Fractional disc-related excess luminosity vs. stellar age for all ISPY targets. PPD targets are shown in red, DEB targets in light blue. The large dark blue asterisk marks HD 203 for which we show the SED in Fig. 7. We note that stellar luminosities were not corrected for extinction such that fractional disc luminositiesare overestimated and appear unphysically large for some of the very young and embedded PPD stars (> 1, light red).