SALT and VLT/X-shooter spectra with Swift-UVOT photometric constraints on the early UV flux. Photons with energies sufficient to ionise the population at 1s2s ³P (λ < 340 nm rest frame or equivalently λ < 280 nm corrected for ejecta expanding at 0.28c) is shown by the red region. The UV flux detected by Swift-UVOT in Evans et al. (2017) decreases with time, falling below the 3σ (2σ) detection threshold after 1.1 days (3.0 days). For comparison with the Swift observations, the maximum UV flux that allows He I to still produce the 1 μm feature (within the Tarumi et al. 2023 NLTE helium model) is shown in black. The Swift flux is around three orders of magnitude larger than what is permitted for the helium interpretation.