Funding for this research was provided by:
Public Health Research Programme
Received: 19 October 2018
Accepted: 4 February 2019
First Online: 12 February 2019
Ethics approval and consent to participate
: Permission to complete this study was obtained from the joint research office of Imperial College London and University of Dundee. The opinion of both institutions was that this study did not require full ethical approval. The study information leaflet was presented to all participants. Electronic consent to participate in the study was provided by participants.
: Not applicable.
: The authors declare that they have no competing interests.
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