Just a couple of points , I checked the John Haycroft who died in Victoria in 1901 aged 50 , thinking he may be Sidney's brother, but by using Samuel as father I did not get a match.
At the NSW archives you can check for inwards and outwards shipping , but it is not indexed , so you have to go through all the film ship by ship. At that time there was a lot of shipping from/to San Fransisco / Sydney via Auckland. If Sidney had come from South America , he most likely had come from SF. I am sure there must be records held somewhere in Auckland for these shipments.