confidentiality

I think this is referring to disclosure that is required (rather than permitted) when the third party is a court/police/lawyer or someone otherwise relevant to legal proceedings. And it means professional interest. It is item iii in this extract from the Code: "There is a professional duty or right to disclose (when not prohibited by law): (i) To comply with the quality review of ACCA or another professional body; (ii) To respond to an inquiry or investigation by ACCA or another professional or regulatory body; (iii) To protect the professional interests of a professional accountant in legal proceedings; or (iv) To comply with technical and professional standards, including ethics requirements." An auditor could not make a disclosure to any third party to protect a personal financial interest (for example).