Representative spectrum taken at 0.34″ from centre of MR 2251−178 (black lines in all panels), and best-fit models (red lines) derived by re-normalising the BLR contribution either as a whole (top panels), or for the red and blue regimes separately (bottom panels), as discussed in the text. The green lines show the contribution of the BLR emission to the full spectrum. The separate normalisation leads to a much better fit to the Hβ line (left panels).