A father jailed for savagely attacking a man who had bitten off his son's ear has won an appeal to have his sentence reduced.

Kevin Allan Hancock, his son and another man rammed the car in which the victim was seated in July 2011.

Armed with a sledge hammer, knives, sticks and a log splitter, they then beat and stabbed the man while he was trapped in the car.

The man suffered a fractured skull, stab wounds, cuts and one of his ears was nearly severed.

Hancock was jailed for seven years and six months after pleading guilty.

He said he had been provoked, because the victim had bitten off his son's ear a few days earlier and had made a further threat against his son.

Hancock appealed against his sentence in the Court of Appeal on the grounds it was manifestly excessive.

In a recent judgment, the court said his sentence was out of line compared to similar cases, and reduced it by nine months.

The serious aggravating factor of vigilante action was neutralised by the provocation and it was relevant that the victim's injuries were not life-threatening and he suffered no long-term damage, the court said.