I'm stumped by my lack of know-how with this Simon. What i have is based on what some authors have reported (in the case of Buntine) and a comment by author Hugh Rethman in his book The Natal Campaign - A Sacrifice Betrayed.
Iro Buntine -
William Harding in his “War in South Africa” wrote: - “It was in the very first fight of the campaign that Dr Buntine, the Victorian surgeon, distinguished himself. The volunteers with whom he served were the first to get touch with the Boers of the Free State commandos as they came through Van Reenen’s Pass. They engaged the enemy but were compelled to retreat, and Dr Buntine seeing one of his men down, rode back under a heavy fire, placed the wounded man behind him on his horse, and rode back in safety with his burden to the regiment. Later on in the campaign it became necessary to discourage brave exploits of this particular kind, and Sir George White issued a general order in which he pointed out that there was no reason to assume that the wounded would be treated otherwise than humanely by the Boers, and consequently it was very undesirable that men should leave the ranks to help a wounded comrade.
Dr Buntine, however, was the first man to attempt the dangerous feat of rescuing a wounded man under fire, and his action was regarded at the time as one which entitled him to the Victoria Cross, for which indeed his name was mentioned, and which he probably would have received but for the necessity which afterwards arose of discouraging similar acts of rescue. Both Dr Hornabrook and Dr Buntine at the very outset of the campaign afforded by their conduct under fire many examples of the cool courage and resourcefulness which have distinguished the Australians all through the war.”
In respect of Brabant: -
Page 138 Rethman - "Subsequently it was recommended that four members of the Imperial Light Horse be awarded the Victoria Cross. They were Major Aubrey Woolls Sampson, Captain Charles Herbert Mullins, Captain Robert Johnstone and Lieutenant A.E. Brabant.
Page 139 Rethman - "In due course a reply was received from the War Office in London stating that while Colonel Woolls Sampson evidently led his men with much gallantry, Lord Wolseley does not feel his conduct was sufficiently exceptional to call for the bestowal of the great favour of the Victoria Cross. With respect to the other three, the War Office apparently felt that all three deserved the award but were only prepared to award two to the regiment. The responsibility of deciding on whom these much prized decorations should be conferred fell on the I.L.H. Adjutant, Captain Barnes. Barnes consulted with the regiment and it was decided that the award should go to Mullins and Johnstone, though all felt that Brabant had also deserved it.
Regards
Rory