Even under UK law and the UK court system their conviction rate is appallingly low, https://victimscommissioner.org.uk/news/the-distressing-truth-is-that-if-you

Even under UK law and the UK court system their conviction rate is appallingly low, https://victimscommissioner.org.uk/news/the-distressing-truth-is-that-if-you-are-raped-in-britain-today-your-chances-of-seeing-justice-are-slim/ https://victimscommissioner.org.uk/news/the-distressing-trut..., to the point where the victims commissioner described rape as effectively decriminalised, https://victimscommissioner.org.uk/document/annual-report-of-the-victims-commissioner-2019-to-2020/ https://victimscommissioner.org.uk/document/annual-report-of.... So he may have got an even lighter or no sentence if tried under UK jurisdiction.