1. Liverpool Clinical Trials Centre, University of Liverpool, a member of the Liverpool Health Partners, Liverpool, UK
2. School of Psychology, University of Liverpool, Liverpool, UK
3. Alder Hey Children’s NHS Foundation Trust, a member of the Liverpool Health Partners, Liverpool, UK
4. School of Healthcare, University of Leeds, Leeds, UK
5. Paediatric Rheumatology, Great North Children’s Hospital, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
6. Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, UK
7. Bristol Royal Hospital for Children, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
8. Paediatric Rheumatology, Nottingham Children’s Hospital, Queen’s Medical Centre, Nottingham, UK
9. Faculty of Health and Life Science, University of Liverpool and Alder Hey Children’s NHS Foundation Trust, members of Liverpool Health Partners, Liverpool, UK