(a) That's right. The Judicial Committee of the Privy Council used to be at the top of the hierarchy of the Australian system of courts, even though it was a foreign (English) court.

The explanation for this is of course found in the colonial history of Australia and the United Kindom.

The right of appeal from Australian courts to the Privy Council was abolished in stages, beginning in 1968 and finishing in 1986. However, references to past appeals are still found in legal source materials.