Footnotes

• Contributors GP: conceptualisation, methodology, data analysis, writing—original draft, writing—review and editing, supervision. DLD: conceptualisation, data collection, coding, writing—original draft, writing—review and editing. BS, JMK: supervision, writing—review and editing.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.