Footnotes

• Contributors RA chaired the project group which designed and implemented the survey, drafted the paper and made the necessary revisions; JB put the survey into an electronic form, analysed the data and reviewed the paper; PJ and MM helped to interpret the survey data and reviewed the paper. FW assisted in interpreting the survey and reviewed the paper. NO reviewed the paper and provided the project with IT support.

• Competing interests None.

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