Funding for this research was provided by:
Medical Research Council
Received: 19 March 2020
Accepted: 23 October 2020
First Online: 7 November 2020
Ethics approval and consent to participate
: All participants gave verbal and written informed consent prior to data collection. This study received favourable ethical opinion from the UK Heath Research Authority and NHS RECs (Phase 1 and 2: London-Hampstead REC, Ref. No. 16/LO/2016; Phase 3: North West-Greater Manchester East REC, Ref No. 17/NW/0501).
: Not applicable.
: The authors declare that they have no competing interests.