Something must have gone wrong with Sidebottom's scheme. The clue is in James Mackenzie’s petition to the governor for his pardon. His submission says,
Your petitioner and James Mossman were driving the sheep three days when your petitioner became very unwell and was obliged to rest one day and immediately on the day of rest, James Moss man went to the top of the hill while your petitioner was lying on the ground unwell, but for what purpose your petitioner could not tell, and he against after diner did the like thing, and remained till towards dusk in the evening of that day when he came running down the hill greatly agitated and exclaimed to your petitioner, “McKenzie? McKenzie? I have done a very bad job. I have stolen these sheep and the owner is coming and is close at hand and I will go away”If Sidebottom had paid Mossman (probably his partner and not his real name) to take the sheep into the Mackenzie country, they would have agreed that he could have four days to get through the pass. Once they were on the other side of the pass on the wide plain, they would scatter out to graze and be hard to find. They would become much harder to track, so Sidebottom would be able to say that the trail had disappeared.
The problem was Mackenzie’s sickness. The drovers had arrived at the foot of the pass on Saturday night, so it would only take a few hours to travel through the pass on Sunday morning. By the afternoon, the sheep would be scattered on the plain and hard to see.
Unfortunately, Mackenzie took sick and Mossman was unable to drive the sheep on his own. The day was lost. The sheep remained on the eastern side of the pass, when they should have been spread on the wide plan on the other side.
Sidebottom seemed to have wasted time for four days to give them time to get away, but he had not counted on them losing a day. When he got near the Mackenzie Pass, he expected the sheep to be well gone. Instead, he had come upon Mossman, who several times during the wasted day had gone to the top of the hill looking for someone. They had an argument and Mossman had fled back to warn Mackenzie. He said that Mossman had a gun, so he might have pulled it on Sidebottom.
With his plans falling apart, Sidebottom had no option but to re-capture the sheep and take them back. So when Taiko returned with his horse Jenny, they carried on tracking and soon came upon Mackenzie watching the sheep. By this time Mossman had bolted, so Mackenzie was captured.
Sidebottom did have some integrity, because he bound Mackenzie loosely and he was able to escape in the fog at night. I presume that he hoped would disappear and not be seen again (as Mossman did). Unfortunately, he was captured in Lyttleton, so Sidebottom was called to give evidence against him.
Maybe the Mackenzie country was actually discovered by John Sidebottom, but Sidebottom Country does not have quite the same ring as Mackenzie Country. And Sidebottom Pass would be awful. It this explanation is true, Mackenzie was an innocent drover, and Sidebottom was double-crossing his employer to stock a run he planned to establish in the land he had discovered, so perhaps it is just as well that the country is not named after him.