1. Centre for Public Health, Queen's University Belfast, Belfast, UK
2. Bristol Trials Centre, University of Bristol, Bristol, UK
3. Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
4. Institute of Nursing and Health Research, Ulster University, Londonderry, UK
5. James Paget University Hospitals NHS Trust, London, UK
6. University of Liverpool, Liverpool, UK
7. Department of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
8. NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, London, UK