Additional fractional uncertainty in S_I for each facet plotted against distance to the pointing centre (blue) and the facet area (red). The additional uncertainty is derived by comparing the distribution of ratios of integrated flux density measurements in each epoch to the deep integration for the 1447 sources detected in the 58 good epochs with a simple simulation using the same sources and errors but allowing for flux density scale offsets between pointings and facets. The consistency of our epoch image integrated flux density measurements decreases with increasing distance from the facet centre and the dashed blue line shows a linear fit to the data using the number of sources in the facet (proportional to marker size) for weighting.