Joint posterior distribution over ξ – the parameter of interest – and , b_ν, ref and σ_ref – the selection effect parameters, based on 1473 projected lengths of LoTSS DR2 giants up to z_max = 0.5. We show all two-parameter marginals of the posterior, with contours enclosing 30% and 70% of total probability. We mark the maximum a posteriori probability parameters (white circle) and the posterior mean parameters (white cross). The single-parameter marginals again show the estimated posterior mean, now marked by a vertical line, alongside shaded median-centred 80% credible intervals. To compare the posterior to the likelihood function, which is also the posterior for a uniform prior, see Fig. E.1.