Inspection maps to evaluate the catalogued polarised source component. Top row: LoTSS 20″ resolution RM map, degree of polarisation map, and polarised intensity map for the catalogued source inside the Stokes I contours (black). Bottom row: FDF with the catalogued RM value and S/N for the peak, and the NVSS 45″ resolution Stokes I (black) and polarised intensity (green) contours for comparison. For the bottom source, the zoomed-in panel show the complexity of the spectrum around the selected peak. After inspection, the top source is accepted, while the bottom source is excluded.