1. Department of Otorhinolaryngology and Head & Neck Surgery, St Mary's Hospital, Imperial College Healthcare NHS Trust, London, UK
2. Department of Otorhinolaryngology and Head & Neck Surgery, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
3. Department of Otorhinolaryngology and Head & Neck Surgery, Queen's Hospital, Barking, Havering and Redbridge University Hospitals NHS Trust, Essex, UK