Funding for this research was provided by:
Wellcome Trust (204796/Z/16/Z)
Received: 21 August 2020
Accepted: 14 December 2020
First Online: 21 January 2021
Ethics approval and consent to participate
: This study used anonymised data collected for non-research purposes and did not require ethical approval.
: Not applicable.
: JW declares that publishing research benefits his academic career.