Comparison of the spectroscopic redshifts of the sources in the z-GAL sample that are single and multiple (where each source has a similar redshift) with the photometric redshifts derived using the methods of Ivison et al. (2016) and Pearson et al. (2013) – blue and red symbols, respectively (as listed in Tables A.6–A.8 and A.1–A.3, respectively). For each source, the two photometric redshift values are linked by a grey vertical line positioned at the spectroscopic redshift value. The solid line shows where the photometric and spectroscopic reshifts are equal and the dashed lines indicate the ±25% deviations. The significant spread here displayed is consistent with previous findings (e.g., Ivison et al. 2016; Reuter et al. 2020; Urquhart et al. 2022) and demonstrates that photometric redshifts, based on Herschel and, when available, SCUBA-2 850 μm continuum flux densities, are only indicative.