In the background, either side of viewing Sal's lampshade, a packet of Smith's chips is visible. Before we see the lampshade, the chip packet is facing backwards, after the scene, the packet is facing forwards.
The scenes that are supposedly inside the High Court of Australia (Federal court located in Canberra) are actually filmed inside the Supreme Court of Victoria and the Victorian Coat-of-Arms are visible behind the judges.
When the characters have their final appeal to the High Court of Australia, it is before 5 Justices. However in reality, when a constitutional dispute is brought before the High Court, all 7 Justices will sit (known as the Full Bench).
When Darryl, his QC and his solicitor are standing in front of the High Court, the building is clearly very modern. When they are inside, in the courtroom, the decor is obviously that of an older style building.