During the attack the victim's teeth were damaged, his lips were split, he received cuts and abrasions to his head, arms and upper body, and his jaw was cracked and he lost consciousness.
Couper then cut off the victim's dreadlocks with a large knife, stuffed them into his mouth and taped it shut. He also taped the victim's wrists together and cut off most of his clothing, leaving him naked apart from a T-shirt.
The victim was then placed in the boot of a car and driven around, before he was left bloodied and naked on the side of the road.
During Couper's sentencing, Judge Peter Hobbs identified the wounding with intent to cause grievous bodily harm as being the lead offence and referred to five aggravating factors, namely planning and premeditation, use of a weapon, attacks to the head, the vulnerability of the complainant and the fact that two attackers were involved.
Justice Hobbs determined that Couper played a greater role in the attack than the other offender and also faced the additional charge of kidnapping.
On that basis, Hobbs imposed a starting point of nine years' imprisonment for both charges, but this was reduced to seven years' imprisonment after a 20 per cent discount was given for a guilty plea.
During Couper's appeal, his lawyer argued the starting point of the sentence was "manifestly excessive" but the judge ruled that Couper's overt culpability clearly justified a starting point of nine years.
Couper's lawyer also argued that personal mitigating factors were not taken into account.
Hobbs ruled there was no merit in this appeal as Couper had shown "little sign of genuine remorse", and had a criminal history for assault and drug offending.
The appeal against Couper's sentence was dismissed.
