She was also sentenced for charges relating to her driving off the road, flipping her car and crawling out of the wreckage before escaping on foot last December.
The agreed summary of facts said that after 7pm on March 23, Henderson doused the caravan in Massey, West Auckland, in petrol and set it alight.
It was soon engulfed in flames and destroyed.
A number of neighbours reported the fire to police, the facts said, and a Herald reporter on the scene at the time said the fire’s black smoke could be seen as far as Henderson.
Police told the Herald then that a witness had seen a woman walking towards the property with a jerry can moments before the fire.
When Henderson was found by police, she was taken to hospital and unable to give a statement but claimed she “can set fire to whatever she wants”, the summary of facts said.
Three months earlier, the woman was driving in Swanson, West Auckland, when she drove off the side of the road and flipped her car.
She managed to get out of the car, which was on its side, and left the crash on foot, the summary of facts said.
She was found by police a 30-minute walk up the road and showed signs she had been drinking. She refused to have her blood tested for alcohol.
While being searched at the Henderson Police station she kicked a female police officer in the groin.
In court, Judge Maria Pecotic read out the victim impact statement of Henderson’s ex-husband.
On the night of the arson, the estranged couple were meant to sign papers for the sale of the house, which didn’t go through because of the fire, his statement said.
He also wasn’t able to claim insurance as Henderson had deliberately set fire to the property, some of which they jointly owned.
His statement said he couldn’t afford to fix, clean or repair the damage, which affected him mentally.
The caravan belonged to another ex-partner and his son’s car had also been “lost” in the fire.
The caravan and carport in Massey, West Auckland, engulfed in flames.
The judge also read out the impact statement of the woman who owned the caravan, which said the impact of the fire had been “devastating”.
The woman was at a particularly low point in her life at the time of the blaze, the statement said, and Henderson’s actions showed a lack of “empathy and compassion” towards her.
She said she was frightened, scared for her life and had to be put into emergency housing, having lost about $80,000 worth of property.
The judge said Henderson had been in a relationship with her former partner for 16 years.
In a Corrections report, the woman admitted to having an alcohol addiction that has lasted 31 years, starting when she was 15 years old.
Being remanded in custody in March was her first time being sober since then, the report said.
There was also an alcohol and drug report before the court that said as a child, Henderson had a fractured relationship with her father, an alcoholic, reconnecting with him when she was 13.
She then had an addiction to methamphetamine that spanned her time overseas and when she moved back to New Zealand.
At some point, there was a parenting order made in favour of her former partner and the woman who owned the caravan, the report said.
Henderson, while consuming a large amount of alcohol and cannabis, had been “ruminating” on “past grievances” related to that order when she set fire to the caravan, the court heard.
Fire crews tending to the Massey blaze in March this year.
Crown lawyer Hugo Wagner-Hiliau said the damage to the caravan, carport and nearby car and trailer amounted to about $107,000.
In sentencing the woman, Judge Pecotic noted the fire was highly premeditated.
This was shown, she said, by witness reports recording that Henderson had gone to a nearby petrol station to get a “jerry can” of petrol.
Members of the public at the petrol station said the woman was announcing proudly what she was planning to do, the judge said.
This was cemented by what Henderson told police upon arrest, the judge said, showing a “clear intent” to start the fire.
The caravan was destroyed “beyond recognition”, and with the carport completely destroyed, the risk of harm was high.
The fire was when people were likely to be at home and it was lucky her children weren’t asleep at the time, she said.
Judge Pecotic sentenced the woman to 28 months in prison for arson.
She was convicted and discharged for refusing to give blood, assault and careless driving in December, but was disqualified from driving for 12 months and a day.
Ella Scott-Fleming has been a journalist for three years and previously worked at the Otago Daily Times, Gore Ensign and Metro Magazine. She has an interest in court and general reporting. She’s currently based in Auckland covering justice-related stories.
Join NZ Herald’s Open Justice team for Case by Case, a video and podcast series examining the disputes and decisions making headlines across New Zealand.