Plots of q(m, c)/n(m, c) for each colour bin of the LR analysis. Lines are colour-coded by galaxy colour bin (running naturally from blue to red); the width of the line is proportional to the number of LoTSS matches at that magnitude, i.e. thicker regions represent the most important regions for q(m, c)/n(m, c) to be determined. The figure clearly demonstrates that the KDE approach for calculating q(m, c) and n(m, c) is able to produce broadly smooth versions of these functions with sufficient magnitude resolution. At fainter magnitudes, the ratio q(m, c)/n(m, c) can be seen to rise monotonically and strongly towards redder colour bins, i.e. redder galaxies have a higher probability to host a radio source, as expected, except at the very brightest magnitudes where nearby star-forming (blue) galaxies contribute significantly.