Footnotes

• Contributors ARH: designed/conceived the idea for our initial survey and collated the guidelines we were sent as part of that study. ARH reviewed the data on the investigations performed in our centre and calculated cost, he wrote majority of the letter. RC, DJAC: significantly contributed to revising project design and the contents of the article. They made suggestions on data interpretation and the articles contents. All authors reviewed drafts of the paper and agreed on the final version. All authors are accountable for the integrity and accuracy of the data submitted.

• Competing interests None declared.

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

• Data sharing statement A number of questions we asked as part of our UK survey (from which we obtained the guidelines) are not reported because they were poorly phrased and did not reveal useful information. The data are available on request from the corresponding author.