Model fits of the JP Tribble spectral ageing model for the northern (left) and southern (right) lobes. Fits in a region with the youngest spectral age (top), lowest reduced χ² (middle), and oldest spectral age (bottom) are shown. The black points with error bars indicate the flux density data pointsin that region and the red line shows the model fit. In the lower left corner of each panel the fitted model, best fitting injection index, magnetic field strength and spectral age in that region, and the reduced χ² values are listed.