Funding for this research was provided by:
Wellcome Trust (200321/Z/15/Z)
Received: 4 July 2019
Accepted: 16 October 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: Approval for the study was obtained from the University of York, Department of Health Sciences Ethics Committee. Written informed consent was obtained from all interview respondents.
: Not applicable.
: The authors declare that they have no competing interests.