Fits with two collisional, three photoionised emission models. A five times over abundance of nitrogen model shown for intrinsic AGN gas only (dashed blue line), starburst emission lines only (dashed green line) and for both intrinsic AGN and starburst gas (thick red line), compared to the same model with solar abundances throughout (thin pink line). The data are binned by two for display purposes. For details see text and Table 3. Left: region around N VII 1s–2p and N VI 1s–3p. Right: region around N VI He-like triplet, including C VI 1s–3p.