Willliam Shelley's father, also William, was the founder of the Congregationalist Church in Australia. He was among the group of missionaries belonging to the London Missionary Society who were expelled from Tahiti in the 1790s, ending up in Parramatta. They did not take no for an answer, however, and continued their missionary endeavour in Tahiti. William Shelley (snr) built himself a ship in Parramatta, called the Halcyon, and used to sail back and forth from Parramatta to Tahiti. He maintained a still in Tahiti, distilling rum which he would ship back to Sydney and use it as currency to buy goods for the mission in Tahiti.

William Bradley's father Jonas Bradley was a sergeant in the NSW Corps, known as the infamous Rum Corps.

So it seems that the sons were disowning the sins of their fathers.