The Duchess, who was appointed Colonel-in-Chief in 2012 by the AMP, said one of the distinctive berets given to her on a previous visit has been fought over by her grandchildren.<br />The Duchess helped cut the cake marking the 100th anniversary of the Corps.<br />She said she was honoured to be there and praised the Regency style building, built by convicts in 1841.<br />She also alluded to her husband Prince Charles's love of heritage architecture.<br />"We stand here this afternoon, at the Australian Army's oldest and most distinguished military barracks," she said.<br />Commissioner Scipione described the presence of the Royals at the police unit as a "great honour".