The very fact that you asked the question explains why the details were contained in a confidential annex. The information is clearly so sensitive that public disclosure of it could potentially prejudice any future proceedings.
I do not subscribe to the view that "the public" have a right to know anything and everything which may be disclosed by members of the public to Public Servants to enable them them to discharge their Statutory functions..
"Freedom of Information" applications have a proper role in ensuring that the State conducts its affairs in accordance with the law, providing the information being sought does not harm those unconnected with the State who have provided information on the understanding that it will remain confidential.
The slippery slope is that information received by a Public Servant to enable a statutory function to be discharged is available to any Public Servant for any purpose, and consequently under the pretext of a Freedom of Information application, the World at large.