She was engaged to transport convicts to Australia and arrived at Portsmouth on 15 October 1797 in order to embark the prisoners. Most of the convicts of the Barwell had been tried in counties in England, Scotland and Wales - they came from Cornwall, Isle of Ely, Cardiff, Bristol, Bedford, Chester, Derby, Exeter, Devon, Essex, Carlisle etc. One prisoner John Macklin, a former soldier of the 86th regt., had been tried at the Cape of Good Hope.
Prisoners awaiting transportation were probably held in one of the hulks. Following is a report from the House of Commons noting the employment of convicts on the hulks during the year 1797.....
The Convicts confined in Langston Harbour were employed under the Orders of the Engineers at Cumberland Fort, as Bricklayers, Stonemasons, Carpenters, Brickmakers and Burners, and as Labourers in removing Earth, Gravel, and Mud, and in forming Glacis, and in various other Works, as ordered by the Superintendents. Those confined in Portsmouth Harbour were employed under the Orders of the Engineers at Weevil Lines, near Gosport, as Bricklayers, Stonemasons, Carpenters, Sawyers, Wheelwrights, and Blacksmiths; and as Labourers, in removing Mud and Gravel, raising, sloping, and preparing Glacis, and other occasional Works, as ordered by the Superintendents. The Convicts cannot be employed but in clear fine Weather, for in dark foggy Weather, which happens very often, but particularly at Cumberland Fort, there would be great danger of their effecting their Escape. A great Number of the Convicts on board the above Hulks were rejected as unfit to proceed to Botany Bay at the several Transportations, and many received from the Gaols are so emaciated by long Confinement, and Debility arising from former Debaucheries, that they are unable to work; to these add the Number necessarily employed in keeping the Ships and Wards clean, and they will amount to nearly One Third of the whole Number confined. 
Departure from Portsmouth
The Barwell departed Portsmouth on 6 November 1797 sailing in convoy of the Niger frigate and several other vessels. 
The NSW Corps formed the guard, Ensign Nicholas Bayley in command
Passengers included Richard Dore, deputy Judge-Advocate.
In correspondence by the Duke of Portland to Governor Hunter dated September 1797 some of the free passengers are referred to: You will also receive in a separate cover the plan of a corn mill with the books mentioned in the margin. The undermentioned persons who are carpenters, but who have lately been attending to the building and construction of corn mills go as settlers by this conveyance. 
Three families were granted permission to become free settlers in New South Wales in August 1797. They were to be given passage and victualling for the voyage and accommodation for their convenience was made on the Barwell. They included John Bowman, wife, two sons and one daughter; Andrew McDougall, wife, four sons and one daughter and John Smith, wife, three sons and one daughter. 
The Barwell took the passage via the Cape of Good Hope. Soon after leaving the Cape, there were whispers of a mutiny and but for information given by one of the men, it may have taken place. Ensign George Bond of the New South Wales Corps was named as one of the ringleaders. He and several other soldiers were thrown into irons.
Later, in the colony various charges were made against several men as well as George Bond, however they came to naught at trial. Members of the NSW Corps mentioned at the ensuing trial included John Murray, William Hallam, Gregory Belloe, James Nevil, Patrick Welch, John Brown, John Broadbent and Ensign Bayley.
3). In 1810 the following people who had arrived on the Barwell received their Certificates of Freedom being restored to all the Rights of Free Subjects in consequence of their terms of transportation being expired...Thomas Evestaff, Abraham West, Thomas Sealy, James Wild, William Barron.
4). Convict lawyer/poet Michael Massey Robinson - Extract of a letter from a gentleman who went passenger in the Barwell to New South Wales. September 5, 1798.....Mr. Robinson, the attorney, whose memorable attack upon Mr. Oldham produced so memorable a prosecution against him, came also in the Barwell; and from the superiority of his manners and behaviour, ingratiated himself so happily with the captain and officers as to be allowed a situation entirely remote and detached from the convicts, where, in a mess composed of some passengers, the boatswain, gunner, and steward, he was indulged every day with a bottle of wine and a cover from the captain's table. 
6). John Cadman who became Superintendent of Government boats in Sydney also arrived on the Barwell. Cadman Cottage - Dictionary of Sydney
7). Convict artist John William Lancashire arrived as a convict on the Barwell. In about 1803 he produced this painting of Sydney Cove. The bridge over the Tank Stream can be seen on the far right. Find out more about convict artists here. Read the trial of John William Lancashire at The Records of the Old Bailey Online
8). Judge-Advocate Dore to Sir Michael Le Fleming.
Table Bay Cape of Good Hope, from on Board the Barwell........
Dear Sir Michael
Monday 5th February 1798
The Barwell sailed from Portsmouth bound for Botany Bay, with 296 male convicts, eighteen free settlers for the colony, thirty-one soldiery, crew, etc., 422 total. We all arrived with the loss of three convicts only, after a passage of the finest weather ever known, in Table Bay, Cape Town, January 20th, 1798, where we are expected yet to remain a month longer. All healthy and well, and no reason for tarry or detainure. ....... We sailed under convoy of the Niger, frigate, and several other sail, all of whom we left at the Madeiras, but the Barwell being a remarkably fast sailer we got here long before them, although with calms and adverse winds we lost a fortnight..... We have not yet experienced anything very refractory - twenty five in number had meditated a rise, when the sailors were aloft, to seize our cuddy arms and take the ship etc., by the murder of us all - but one impeached the preceding evening, and in the morn they were called up and every soul double ironed and coupled in pairs........ I have the best accommodations possible. The starboard side of the round house, stern gallery etc., for self and Richard (son). I took a hairdresser's servant from London with me. Have a good mess with the captain, and plenty of black strap and fresh provisions which every day is served throughout the voyage; pigs, sheep and poultry of all kinds being plentiful stores from the Isle of Wight when we embarked. Cape living is most vile - beef, carrion; butter, soft and oily; nothing good, fruit excepted, which is in great abundance and cheap; cheese and butter, intolerably bad. Some charming women, admirable walkers, and expert in dancing and music. The men are Jews in nature; eating, drinking smoking, and sleeping is their whole employ. Horses, the vilest of their kind. Multitude of soldiery, horse and foot.......Historical Records of New South Wales, vol., 3, Hunter 1796 - 1799 pp. 355,356
9). In 1803 the above-mentioned George Bond published A Brief Account of the Colony of Port Jackson detailing the process of disembarking...... When a ship arrives at Port Jackson the captain, according to custom, waits upon the governor, with an account of the voyage, stores, the number of male and female convicts etc.,, In a few days after their arrival, the male convicts have their irons taken off, are well washed and cleaned and are furnished with a change of clothes, and other necessaries. After this previous preparation, the governor, commissary, and others, go on board, when all the convicts are ordered upon deck, and each person's name called over, and inquiry made what trade or profession each has followed, whether tailors, shoemakers, masons, etc. They are then classed according to such their former employments, and continue to exercise their usual trades. Labourers, and such as have had no regular business, are usually assigned to the officers and settlers. 
10). Soldier of the 86th regiment John Macklin was court-martialled for mutinous behaviour. He was later sent to Van Diemen's Land where he received an Absolute Pardon. He was still alive in 1823.
The mutiny act, section 4. declares, ' that when a court martial shall not think the offence (of desertion) deserving of capital punishment, such court may, instead of awarding a corporal punishments adjudge the offender to be transported as a felon for life, or for a certain term of years; and if such offender shall afterwards, without leave, return into Great Britain or Ireland, before the expiration of the term limited by such sentence, he shall, on conviction thereof, be deemed and adjudged guilty of felony, and shall suffer death as a felon without benefit of clergy.' In this place it may not be improper to make a few remarks on the sentence of a general court martial, held at the Cape of Good Hope (November 1797), upon the trial of John Macklin, a private soldier of the 86th regiment, who being found guilty of mutinous behaviour, was adjudged ' to receive one thousand lashes in the usual manner, and be transported for life to Botany Bay.' - Principles and Practice of Naval and Military Courts Martial: By John McArthur, p.202
10). Convicts of the Barwell identified in the Hunter Valley..........
John Clues/ Clews
 HR NSW, vol. IV p. 787
 HR NSW, vol., III, p. 728
 HR NSW, vol., III p. 285
 HR NSW, vol., III, p. 301
 Reports from Committees of the House of Commons: Volume 13 p. 385
. A brief account of the colony of Port-Jackson, Volume 13 By George Bond (lieutenant of marines.) p.7