A later comment suggests the Chatham house website is sympathetic to my interpretation:
Q. Can participants in a meeting be named as long as what is said is not attributed? A. It is important to think about the spirit of the Rule. For example, sometimes speakers need to be named when publicizing the meeting. The Rule is more about the dissemination of the information after the event—nothing should be done to identify, either explicitly or implicitly, who said what.
A later comment suggests the Chatham house website is sympathetic to my interpretation:
Q. Can participants in a meeting be named as long as what is said is not attributed?
A. It is important to think about the spirit of the Rule. For example, sometimes speakers need to be named when publicizing the meeting. The Rule is more about the dissemination of the information after the event—nothing should be done to identify, either explicitly or implicitly, who said what.