Funding for this research was provided by:
Health Technology Assessment Programme (HTA 10/32/02)
Received: 27 March 2018
Accepted: 6 December 2018
First Online: 22 January 2019
Ethics approval and consent to participate
: Ethics approvals were obtained from NRES Committee London – Hampstead REC reference: 12/LO/0219. Written consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.