Data SEDs (top left) and dust model I_λ/ ℛ, normalised by the median data SED (U_min = 0.66) to highlight the spectral shape variations. The model SEDs are computed using as ISRF intensity (Sect. 3.2). The same five SEDs as Fig. 1 are shown, for clarity of illustration, using the same colour and line style scheme. The observations are plotted in grey behind the models to aid comparison.