Hi Leigh,
Re... "
So the next part of the puzzle is to find out whether there were two different William Titleys in Queensland, one of whom left Queensland permanently in 1858/59, or whether there was one William Titley, who divorced & remarried."
Maybe you have a typo?? "left Queensland permanently in 1858/59"; should be 1888/89?
I may have given you the link previously, for QLD BDM's. which you can purchase and download instantly???
https://www.bdm.qld.gov.au/IndexSearch/queryEntry.m?type=bir...1885 B9645 (Bride) Mary Ann Sheehan (Groom) William Titley
Here is the birth of that child... Mary Louisa TITLEY, in 1886.
1886 B36300 Mary Louisa Titley (Father) William (Mother) Mary Ann Sheehan
Mary