[Cii] luminosity vs. the CO(1–0) luminosity for the VALES sample at 0.03 <z< 0.2 superimposed on the low- and high-z samples taken from Fig. 7 of Gullberg et al. (2015), with symbols as specified in the legend. Downward triangles represent 5σ upper limits. The grey shaded region the 1σ spread in the mean observed L_[Cii]/L_CO ratio (3500 ± 1200; blue dashed line) of our sample, which we compare to the mean ratios of the low-z sample (1300 ± 440; black dotted line).