[1] Univ Manchester, Sch Nursing Midwifery & Social Work, Manchester M13 9PL, Lancs, England
[2] Univ Lancaster, Div Hlth Res, Lancaster LA1 4YF, England
[3] Cheadle Royal Hosp, Eating Disorders Unit, Cheadle SK8 3DG, Cheshire, England
[4] Pennine Acute Hosp NHS Trust, Manchester M8 5R, Lancs, England