1. Nuffield Department of Anaesthetics; Oxford University Hospitals NHS Foundation Trust; Oxford UK
2. The Royal National Throat Nose and Ear Hospital; London UK
3. Ninewells Hospital; Dundee UK
4. Warrington Hospitals NHS Foundation Trust; Cheshire UK
5. Queen Elizabeth Hospital; Birmingham UK
6. Portsmouth Hospitals NHS Trust; Portsmouth UK
7. James Cook University Hospital; Middlesbrough UK
8. New Victoria Hospital; Glasgow UK