1. University of Oxford; Health Services Research Unit, Nuffield Department of Population Health; Old Road Campus, Headington Oxford UK OX3 7LF
2. University of Aberdeen; Health Services Research Unit; Health Services Building Level 3 Foresterhill Aberdeen UK AB25 2ZD
3. University of Oxford; Department of Primary Care Health Sciences; 23-28 Hythe Bridge Street Oxford Oxfordshire UK OX1 2ET
4. University of Oxford; Quality and Outcomes Research Unit and Health Experiences Research Group; 23-28 Hythe Bridge Street Oxford Oxfordshire UK OX1 2ET
5. University of Oxford; Nuffield Department of Population Health; Rosemary Rue Building, Old Road Campus Headington Oxford Oxfordshire UK OX3 7LF
6. University of Oxford; Nuffield Department of Primary Care Health Sciences; Radcliffe Observatory Quarter Woodstock Road Oxford UK OX2 6GG