The defence showed that they found ID for Matthew Hartley in the rafters along with the hard drive. They showed DG purchasing goods at Princess Auto with a TD card issued in the name of Matthew Hartley. (They had the receipt showing the name on the card AND they had the video to show that it was DG using it.) I don't think it matters that they can't say he was charged with identity theft. They've proved the link they needed to prove.
I didn't realize he had used MH's debit card for that. That makes sense then.