Multi-wavelength SEDs for four example SMGs that demonstrate the range of observed-frame infrared colours displayed by the SMG sample. Appendix B shows the SEDS for the full sample. For each source, we indicate the observed flux and error in each band with a red circle and error bar. Arrows show upper limits at 3σ. We over-plot the best-fit magphys derived SED (orange line) and model fluxes (black circles). Below each SED we display the probability distributions of the MAGPHYS derived properties: redshift (unless spectroscopic), stellar mass and A_V, and report the best-fit redshift and reduced χ² from the fit in the top right. Above the SED we display the multi-wavelength JWST and ALMA 870 μm imaging used as part of the analysis, with the SMG centroid indicated by the red tick markers.