SLIMBH and BHSPEC versus the phenomenological 2-component model. The black hole mass, α and inclination are fixed at 10  M_⊙, 0.01 and 30°, respectively, and the black hole spin is tied, a_∗ = 0.36. All three models represent best fits. The data are well described by the physical disc models at the highest luminosity, but are significantly broader at lower luminosity. Left: low luminosity disc (L = 0.27  L_Edd). Left: high luminosity disc (L = 0.86  L_Edd).