1. Southampton Health Technology Assessments Centre (SHTAC), Wessex Institute for Health Research and Development (WIHRD), University of Southampton, Southampton SO16 7PX, UK
2. Fourth Hurdle Consulting Ltd, Holborn Tower, 137–144 High Holborn, London WC1V 6PL, UK
3. Department of Public Health, School of Medicine, University of Aberdeen, Polwarth Building, Aberdeen AB25 2ZD, UK