1. Health Economics and Policy Research Unit, Faculty of Health Sport and Science, University of Glamorgan, Mid Glamorgan, UK
2. Department of Primary Care and Public Health, School of Medicine, Cardiff University, Cardiff, UK
3. Section of Pharmacology, Therapeutics and Toxicology, School of Medicine, Cardiff University, Cardiff, UK
4. Centre for Economics and Policy in Health, Bangor University, Bangor, UK