Attempt to reproduce the pseudo-bolometric light curve with a simple analytical diffusion model. All three components of the model are shown along with their total, which fits the observed luminosity well. The model is somewhat degenerate, and the details of this are discussed in the text, as are the parameters. The best-fitting explosion epoch from our modelling is MJD 59 669.38, which is consistent with our adopted outburst epoch (MJD 59 667.98 ± 1.5).