Footnotes
Contributors: All the authors participated in designing the study and interpreting the data. All the authors critically revised the manuscript. All authors were involved in the development of the protocol, validated topic guide, and interpretation of the analysis. ES conducted the focus groups, transcribed and analysed the qualitative data and wrote the first draft of the manuscript. The corresponding author attests that all listed authors meet authorship criteria and no other meeting criteria have been omitted.
Transparency declaration: The lead author, Eleanor Sein, affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.
Funding: no external funding
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work, all authors are affiliated with Imperial College London as educators; no other relationships or activities that could appear to have influenced the submitted work.
Provenance and peer review: Not commissioned; externally peer reviewed