1. Clinical Operational Research Unit, University College London, London, UK
2. NIHR CLAHRC Wessex Data Science Hub, University of Southampton, Southampton, UK
3. University of Exeter Medical School, University of Exeter, Exeter, UK
4. Emergency Department, University Hospital Southampton NHS Foundation Trust, Southampton, UK
5. Emergency Department, University College London Hospitals NHS Foundation Trust, London, UK
6. Department of Applied Health Research, University College London, London, UK