The Sydney Gazette reported Major Sullivan's arrival in October 1828.....
On Monday last arrived, from Liverpool and the Cape of Good Hope, having left the former place the 26th March and the latter the 23rd July, the ship Mary Hope, Capt. Farmer, with a cargo of merchandize. Passengers Major Sullivan, Mrs. Sullivan, and four children; Surgeon Duncan; Mr. and Mrs. William McLean; Mr. D. McLean, Mr. Thompson, Mr. Bell; and three steerage passengers. 
Jane Bell age 28 came as a free servant to Benjamin Sullivan.
Major Sullivan was mentioned in the Australian a few days later when Colonel Snodgrass' arrival was imminent - We understand that the officer who is expected out very shortly as Major of Brigade, is not Major Snodgrass, the distinguished Military Secretary at Ava, and author of a Narrative of the Burmese War, as has been supposed and as we have more than once stated, but Colonel Snodgrass, a brother of that officer's who distinguished himself during the late war, at the taking of St. Sebastian's. Two of the Colonel's brothers-in-law, Major Sullivan, an officer who lately sold out with the view of settling in New South Wales, and Mr. W. McLean, Esquire late of Paisley, arrived in the Colony with their families a few days ago per the Mary Hope. But we regret to add that the only son of the latter of those gentlemen, a very promising and accomplished young man of 17 years of age, was unfortunately seized with consumption on the passage out, and died a few hours after the ship had dropped anchor in the Cove. 
In the 1828 Census taken in November the family are listed as lodgers residing at Sarah Waples', 104 Pitt Street Sydney. Benjamin Sullivan was 43 years of age, Margaret 38, son John Henry 12, Benjamin Robert 10, Charlotte Albinia 7 and Margaret Isabella 4 years of age 
Benjamin Sullivan was granted 2560 acres of land in the county of Durham in 1828. The estate was known as Thalaba
Assigned Convict Servants
Convicts assigned to Benjamin Sullivan at Thalaba included:
Thomas Ryan arrived per Norfolk.
John Bright arrived per Portland
Edward Baker arrived per Lady Harewood.
William Burley arrived per Prince Regent
Benjamin Anderson arrived per Lady Harwood.
Richard Bickerton arrived per Captain Cook
James Cruickshanks arrived per Glory
John Byrne arrived per Captain Cook
John Weston arrived per Surry
John Anstiss arrived per Portland
James Lonergan arrived per Norfolk
Edward Green arrived per Midas
Thomas Smith arrived per Lord Melville
Henry Wood arrived Norfolk in 1829
John Kidd arrived per Norfolk
Thalaba Offered for Sale
In 1833 the estate was offered for sale.......
The valuable estate of Thalaba at Williams River the property of Major Sullivan containing 2560 acres will be brought to the hammer on Thursday next SH 2 May 1833. This splendid estate is situated on the left bank of the Williams' River, eight miles from Clarence Town, bounded on the North by an imaginary line extending from Williams' River to the Church and School Lands, adjoining the Grant of the Australian Agricultural Company, dividing it from the unlocated Lands of the Crown, between it and Mr. Myles Grant ; on the South and West by the Williams' River, dividing it from the Grants of Messrs. Mackay, Hooke, and Verge, and from the Township Reserve of Wallarobba; and on the East by Thalaba River alias Wonga Wonga Creek. Thalaba is free from all Quit rent ; has a right of working coal, of which it possesses an abundance, large tracts of brush alluvial soil, a variety of excellent timber, cedar forming the greater part, limestone of the first quality is here found, which at all times will find a ready sale ; the soil is well adapted for every sort of cultivation, particularly for the growth of tobacco, the finest crops having been obtained ; the pasture is excellent both for horned cattle and sheep, with plenty of water in the driest seasons ; there is an immense back run ; there are about forty acres cleared, and at a trifling expense, 200 acres more could easily be added ; a five railed stock-yard, several huts for the accommodation of a family and domestics, and for storing grain, pigsties, a large garden, etc. The whole forming one of the most valuable properties a Settler could possibly desire to possess, and from which a large return may be easily made the first year. This Estate will be divided, if desired, at the time of sale 
On 9th June 1832 Benjamin Sullivan was appointed first resident Magistrate of Port Macquarie and embarked with his wife and family on the Governor Burke for that place late in June 1832. He held this position until 1835.
His son John Henry Sullivan was awarded a prize in connection with the Australian College in October 1832....The second prize of Books for an Essay 'on the marks of wisdom and power in the works of nature and the mode of tracing these as effects to one intelligent cause' was adjudged to John Henry Sullivan. (The first prize was awarded to Master John Snodgrass (son of Col. Snodgrass) 
Benjamin Sullivan was appointed Police Magistrate at Raymond Terrace in 1837. His wife Margaret nee Snodgrass died of apoplexy at Brandon Hall on 19th February 1838.
Margaret Sullivan's sister Jessie MacLean nee Snodgrass died at Kilray, Raymond Terrace on 31st October 1839 - Jessie the wife of William McLean Esq., daughter of the late Rev. John Snodgrass D.D Minister of the Middle Church, Paisley and sister of Colonel Snodgrass C.B. late Acting Governor of the Colony.
In October 1839 Charlotte Albinia the daughter of Benjamin Sullivan and his first wife Margaret married Rev. Wilton at Newcastle.
Benjamin Sullivan was appointed Police Magistrate at Cassilis in 1840.
He was interested in colonizing Australia and promoting emigration and in 1841 proposed land colonization companies in Queensland, Victoria and New Caledonia - Asiatic Journal
Major Sullivan was appointed police magistrate at Wollombi in 1847 replacing David Dunlop. He married Isabella Barbara Ogilvie, widow of Peter Grant Ogilvie at the Court House Wollombi on 16th May 1847.
Benjamin Sullivan as an Inventor
Benjamin Sullivan claimed to be the inventor of Indian rubber pontoons and, in 1848 produced correspondence from Lord Viscount Beresford, Master-General of Ordnance dated 14 April 1827 confirming the invention and informing him that it had been submitted to a committee at Woolwich for consideration and report.
He died at Wollombi in 1860 - At his residence Aberdour, Wollombi, on Friday 26th April in the 76 year of his age. The deceased gentleman as a retired field officer of the British army and the only surviving son of the late Sir Benjamin Sullivan, Baronet a distinguished officer of the same service. Major Sullivan was an old and respected colonist and for many year filled the offices of Police Magistrate and Coroner for the district of Wollombi. His death is much regretted by a wide and respectable circle of relations and friends amongst the former of whom is a much devoted and inconsolable widow.