1. Department of Psychology, Addiction and Mental Health Group University of Bath Bath UK
2. Department of Psychology, Addiction and Mental Health Group, Bath Centre for Mindfulness and Compassion University of Bath Bath UK
3. Bristol Randomised Trials Collaboration, Population Health Sciences Bristol Medical School Bristol UK
4. Department of Population Health Sciences, Bristol Medical School, Centre for Academic Primary Care University of Bristol Bristol UK
5. MRC Integrative Epidemiology Unit, School of Psychological Science University of Bristol Bristol UK
6. Nuffield Department of Primary Care Health Sciences University of Oxford Oxford UK