Well I found my buried records.
Death Registration of John McCrohon 20 June 1900 at Tingha NSW Born Portugal in Aust 58 years, Parents John McCrohon Quartermaster Sergeant in the army, Mother Emily Ducroi (x, more like t, possibly c). When this John's son (another John died) his obit said he was the son of Mr. & Mrs. Patrick McCrohon who had migrated to Australia from Ireland.
Then the youngest child of John and Emily - Louis Estall died 3 May 1924 parents John McCrohon Miner and Agnes Decrow? (informant his son)
No wonder things are confused...
I.M. another researcher says in 2000: John - Born St. John's Parish, Limerick July 1795, Brother William born Jan 1807 Crondon Park, Essex. John christened son of John and Margaret Crondon Park Rc 1 March 1807. Military Service - Returned Winchester 1 April 1826. Emily Ducroix Born France ca 1800 Seamstressi n Parish at time of British occupation 1816. First marriage to - Banham? John and Emily married 23 June 1826 at St. Thomas Rc Winchester.