Emission line diagnostics plot for UV high ionisation lines. Top panel: C3He2 versus [Ne IV] λ2424/C III], Middle Panel: C3He2 versus [Ne V] λ3427/C III] diagnostic diagram, Bottom panel: C3He2 versus N V λ1240/C III]. We plot our objects detected in high ionisation lines as blue points. The yellow and light blue points show star forming and AGN from photo-ionisation models from Feltre et al. (2016), Gutkin et al. (2016) (see Sect. 2.4). We highlight the emission line ratios of GN-z11 (Maiolino et al. 2024a) as the magenta star.