Laing had been recovering from the July 31 assault at Ezmeralda's Cafe in Papakura, where he had taken his family for dinner, but was keen to get back to work because the family needed more money than he was getting on ACC.
An "enraged" Cleven entered the cafe at around 5.20pm, soon after Laing, and yelled, "You cut me off", as he walked up to him, according to a police summary of facts.
He wanted an apology for the incident at the traffic lights outside, but didn't give Laing a chance to speak.
Laing turned to face Cleven, who punched him twice in the face with a closed fist. The blows knocked Laing back and made him lose his balance and stagger.
His left eye was bloodied by the attack and the vision was blurry. He was judged unfit to work until he received a further medical assessment to ensure it was healing.
Cleven's lawyer, Peter Winter, alleged Laing's partner subsequently assaulted Cleven, leaving him with a bruise on his nose, and that Laing, outside the cafe, threw a sandwich board at Cleven's car, causing damage that cost more than $1200 to repair.
The prosecuting lawyer, Frances Gourlay, said she had watched CCTV footage from a camera inside the cafe. It did not show the alleged acts of retaliation on Cleven.
Cleven pleaded guilty at his first court appearance and had wanted to apologise to Laing through a restorative justice process, but Laing died in the meantime.
Winter said Cleven was of good character and although he was convicted of assault in 2006, it was a minor matter.
The judge noted the glowing references about Cleven, a "very pro-social member of the community", but he said the attack on Laing was a serious assault.
"The issue of road rage in this country seems to be one that is becoming more frequent. That too is wholly regrettable and in my view the courts need to draw a line in the sand where road rage events result in loss of self-control by a defendant and an assault occurs."
"It's not something the courts can pass over lightly or in any way condone."
Laing's father, Doug Laing, a Hawkes Bay Today journalist who was in court with many relatives, said later he accepted Cleven was not responsible for his son's death.
But in a victim impact statement to the court, he said: "We all believe strongly that had it not been for the attack by John Cleven, then Leslie would be alive today. He would be able to continue providing for the children for whom he lived.
"They must now face a life without their father, but with the nightmare of the attack in Papakura two months ago."
