[N II]- and [S II]-BPT diagrams for the disc and outflow components, as shown in Fig. 6, colour-coded as a function of the [O III] velocity dispersion (darker shades means higher σ_{[O III]}). The grid of shock models taken from Allen et al. (2008) comprises shock velocities in the range v_s = 100 − 1000 km s⁻¹ (horizontally increasing) and magnetic parameters B/n^1/2 = 10⁻² − 10 μG cm^3/2 (vertically increasing). The black dotted line is the Kewley et al. (2006) boundary between Seyferts and LI(N)ERs.