Again, Mr. Reid posed four questions in his letter. It's a very comprehensive treatment of the subject and, as one might expect, Mr. Reid is very skilled in such matters.
The first question is basically to ask what steps members of the committee might take to discharge their obligations under the relevant provisions of the act. Basically, the short answer to that, which might seem self-serving, is go to see a lawyer and get some legal advice, but you should probably return the document.
You know you have a document. You should know the circumstances. You may have reason to believe you don't have lawful entitlement to the document and you're not meant have it. It's governed by this act. I'd assume you'd have time to read the act and get some legal advice. But at the first opportunity, once you're satisfied that is the case or could be the case, you'd be wise to return the document to its apparent owner.