Predicted GC numbers as a function of magnitude. Panel a: Specific frequency of GCs as a function of host galaxy magnitude for our galaxy catalogue. Panel b: Total GC number in each galaxy as a function of its magnitude. A polynomial fit to the data is shown as orange line. Panel c: Log difference between the mean GC number for a given galaxy magnitude (orange fit in the middle panel) and the actual GC number of each galaxy. The alignment of data points in the bottom half is a natural consequence of the small numbers of GCs where the difference is only a single or two GCs for those low-luminosity galaxies.