1. Faculty of Health and Applied Sciences, University of the West of England, Glenside Campus (1H14), Blackberry Hill, Bristol BS16 1DD, UK
2. South Western Ambulance Service NHS Foundation Trust, Eagle Way, Exeter EX2 7HY, UK
3. Centre for Academic Primary Care, Bristol Medical School, University of Bristol, Whatley Road, Bristol BS8 2PS, UK
4. Research Design Service – South West, University Hospitals Bristol NHS Foundation Trust, Upper Maudlin Street, Bristol BS2 8AE, UK
5. Emergency Department, Bristol Royal Infirmary, University Hospitals Bristol NHS Foundation Trust, Bristol BS2 8HW, UK