Henry Gordon Brock was the son of James Brock and was born about 1790.
He was appointed assistant surgeon on 24 August 1812. He was appointed assistant surgeon to the Leander in 1819
Edinburgh Medical and Surgical Journal July 1825 - On the 1st August, the Senatus Academicus of the University of Edinburgh conferred the degree of Doctor in Medicine on the following Gentlemen in number one hundred and forty, after having gone through the appointed examinations and defended publicly their inaugural dissertations. Among the graduates was Henry Gordon Brock - (Tetano)
In 1828 he was employed as surgeon-superintendent on the convict ship Marmion (to VDL). He kept a medical journal from 15 October 1827 to 14 March 1828.
His next appointment was to the Surry which sailed from Spithead in August 1829.
Henry Brock was appointed to the convict ship Argyle in 1831. The Argyle sailed for Van Diemen's Land with 250 convicts of which 150 were embarked from the Captivity hulk. It was reported in the Hampshire Advertiser that convict ships had never left Plymouth with so great a proportion of notoriously desperate characters as the Argyle. ....'we augur favourably respecting the issue of her voyage, from the experience of the Medical Officer in charge of the convicts, who has accomplished three voyages in that service, and also the increase and efficiency of the guard, which has been effected by orders from the Commander in Chief'
On his return to England he married Elizabeth Caroline Barnes on 17 July 1832 at St. John the Evangelist, Westminster, Middlesex.
Van Diemen's Land
In 1833 he was appointed to the Lotus, which arrived in Van Diemen's Land in May 1833. While in Hobart at this time he commented on the living quarters on convict ships.. In 1834 he was surgeon on the William Metcalfe (to VDL).
New South Wales
In 1836 he was employed as Surgeon-Superintendent on the Thomas Harrison which brought 112 female prisoners to New South Wales.
Immigrant Ship Orontes
He was on the List of Surgeons remunerated for services as Surgeon Superintendents. He was paid £200 for his employment on the immigrant vessel Orontes which arrived in Sydney on 18 May 1838.
He was on the list of Medical Officers who received pensions for wounds received in the service - 16 December 1843 (Navy List)
A widower by 1854, he married Eleanor, the eldest daughter of Edward W. Jenkyns of the Stock Exchange on 1st August 1854 
Henry Gordon Brock died in 1862 -
Notice: - On the 16th inst. at Burleigh House, (Burial Records states Holly House) Old Brompton, Dr. Henry Gordon Brock, R.N., of the Red Rock, Tasmania. - Morning Post 19 December 1862. His estate was valued at under 600. The addresses on his Will were Clarendon Lodge, Kensington Park and afterwards 10 Sidney street Fulham road and lately of Burleigh House Old Brompton all in the County of Middlesex. Administration was granted to his son, the Rev. Frederick Davies Brock of St. Marys terrace Scarborough 
 Hampshire Advertiser 26 March 1831
 The Standard 3 August 1854
 Ancestry.com. England and Wales, National Probate Calendar