[1] GP & Natl Inst Hlth Res NIHR, London, England
[2] Keele Univ, Sch Med, Keele ST5 5BG, Staffs, England
[3] Univ Warwick, Warwick Med Sch, Unit Acad Primary Care, Primary Care Res, Coventry, W Midlands, England
[4] Hull York Med Sch, Acad Primary Care, Primary Care Res, York, N Yorkshire, England
[5] Keele Univ, Sch Med, NIHR Sch Primary Care Res SPCR, Keele, Staffs, England