I’m not a legal expert, but it seems that QCs are considerably lower in rank than AGs (there were more than 150 QCs in Scotland alone in 2005). Still, this is an official legal opinion requested by a minister that would carry some weight in UK law, so I don’t see why using the word “find” would be out of place here.
Opinions are usually published at the direction of the court, and to the extent they contain pronouncements about what the law is and how it should be interpreted, they reinforce, change, establish, or overturn legal precedent. If a court decides that an opinion should be published, the opinion is included in a volume from a series of books called law reports (or reporters in the United States). Published opinions of courts are also collectively referred to as case law, which is one of the major sources of law in common law legal systems.