1. Primary Care Unit, Department of Public Health & Primary Care; University of Cambridge School of Clinical Medicine; Strangeways Research Laboratory; Cambridge CB1 8RN U.K.
2. Department of Applied Health Research; University College London; London U.K.
3. Department of General Practice; Melbourne Medical School Faculty of Medicine, Dentistry and Health Sciences; University of Melbourne; Carlton Victoria Australia
4. Betsi Cadwaladr University Health Board; Wrexham Maelor Hospital; Wrexham U.K.
5. Centre of Academic Primary Care; Division of Applied Health Sciences; University of Aberdeen; Aberdeen U.K.
6. North Wales Centre for Primary Care Research; Bangor University; Wrexham U.K.