Footnotes

• Twitter @DrMartinEdwards

• Contributors MOE was involved in the planning and design, and supervised the data collection and helped to draft the first manuscript and all subsequent versions. FH wrote the draft manuscript and helped to collect and analyse the data, and agreed all subsequent versions. SK helped to conduct the study by reviewing all versions of the manuscript and checking for data accuracy.

• 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.