Footnotes

• Contributors NR conceptualised and designed the study, generated the first draft of the manuscript. All authors critically revised the manuscript for intellectual content and edited manuscript drafts; NR collated all authors’ comments for the final submitted version. The corresponding author had final responsibility for the decision to submit for publication. All authors approved the final version of the manuscript.

• 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 Commissioned; internally peer reviewed.