Footnotes

• Contributors FJG is the lead consultant for this child. SB wrote the first draft of this article. SB and FJG edited subsequent drafts and have both approved the final version.

• 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; internally peer reviewed.