Comparison between Grale lens models for the simulated, generalised NFW profile that is detailed in Liesenborgs & De Rijcke (2012). Each plot shows the reconstructed convergence values and their uncertainties (black points with error bars) and the true convergence values (blue points) at the positions of the multiple images measured as radial distance from the centre of the NFW profile for the Grale models with the same constraints as detailed in Table 1 and Fig. 5.