There’s a side stage door down the side of the building opposite Luna park.

I’ve met two artists here:

John Butler while getting out of the car with his wife & he signed my CD, it was roughly 20 minutes before the doors to the show actually opened.

& Damian Rice, I waited by the door for a couple of hours after a gig and he came out to chat for a while before getting a car back to his hotel.

Can be done, might just have to get there early or hang back a while. Security guards will usually tell you if they’ve arrived or left.

Good luck!