I don't think there needs to be a mandate. It's useless in the first place because if the only way to get[/] a minister to listen to advice is to legally require him to hire a panel I don't think he's going to be all that attentive to what they have to say. Second, the panel is diverse but has either been rendered irrelevant or never was. I mean, I'm sure you'll agree that a Neurologist probably would be more useful in discussing policy on LSD than a dentist.
But is there really this problem of Ministers needing to be forced to have advisory boards? Isn't forming advisory boards one of the key responsibility of ministers, and the ability to form good ones one of the key distinction of good ministers? If that's true, why do we have laws that apply a one-size-fits-all solution to how the Minister is to receive advice?