1. School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
2. NHS Lanarkshire Chronic Pain Service, Buchanan Centre, Coatbridge, UK
3. Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
4. University College London Hospitals NHS Foundation Trust, London, UK
5. Department of Social Sciences, Glasgow Caledonian University, Glasgow, UK
6. School of Health and Wellbeing, University of Glasgow, Glasgow, UK