Kreegher then struck the victim with a hammer, knocking him unconscious. Before his kidnappers left, they set the car on fire as the victim lay prone beside it.
"As a result of the offending [the victim] suffered a subarachnoid haemorrhage, a brain contusion, a left temporal fracture, a nasal and left orbital fracture, and first-degree thermal burns to his hands and arms," the Court of Appeal decision said.
"He underwent surgery and was hospitalised for several days, followed by rehabilitation."
Kreegher was sentenced as the principal offender, while Turner was sentenced on the basis there had been an unlawful and premeditated common intention between them to assault and rob the victim. A third defendant was acquitted of all charges.
Kreegher had been found guilty of kidnapping, aggravated robbery, arson, and wounding with intent to cause grievous bodily harm. He received a prison sentence of eight-and-half years.
He appealed the conviction and sentence in the Court of Appeal, arguing the verdict was unreasonable because there was insufficient evidence of his guilt, the prosecutor misdirected the jury, and that the judge wrongly cautioned the jury about the reliability of the victim's evidence.
Kreegher's lawyer, Elizabeth Hall, told the court the case was loosely circumstantial and rested largely on the identity of one of the cars used in the incident, rather than the occupants.
But the Court of Appeal disagreed on the grounds of appeal against conviction, and dismissed that section of the appeal.
Hall also argued the sentencing starting point was too high and that the discounts given were insufficient.
The Court of Appeal disagreed the starting point was excessive, but said the discount of 5 per cent for Kreegher's personal mitigating circumstances was "manifestly inadequate".
"This is a case where a meaningful discount for Mr Kreegher's difficult upbringing and deprived social circumstances is available," the decision said.
Kreegher is of Māori and Pākehā descent and identifies strongly as Ngāpuhi, but grew up in a household where his European father did not encourage taha Māori in the home.
His father was a violent man and Kreegher was mistreated by his stepmother, the decision said.
He had been an active member of Black Power since a young age, but said he had since left the gang.
Kreegher also said he abuses alcohol and started using meth and other drugs at 17.
Hall said Kreegher was also kicked out of home at the age of 12 and bounced around relatives until he ran away at 15, and that he was homeless for a number of years.
"We are also satisfied that these same issues, and more generally a life marred by social deprivation, including at the time of the offending, likely influenced Mr Kreegher's poor life choices general and on the night in question," the decision said.
The court agreed to raise the discount to 10 per cent to account for this. It also granted a further 5 per cent discount for the three years Kreegher spent on bail awaiting trial and sentence.
With the new discounts factored in, the Court of Appeal settled on a new final sentence of seven years and seven months' imprisonment.
