Police later won a High Court appeal to have the matter reheard by another District Court judge.
Mullany returned from Britain (where she was working in the polo industry) during November to appear before Judge Tony Adeane.
He lifted suppression and disqualified her from driving for the mandatory minimum period of nine months.
Judge Adeane cut short Mrs Insley's submissions, urging her not to risk placing her client further in the spotlight. There was still no concrete evidence presented of actual consequences for Mullany, should the conviction endure, he said. She had been given the earlier reprieves unfairly.
People from all walks of life had been similarly convicted, without ruinous effects on their careers, he had said.
But Mrs Insley immediately lodged another appeal.
She appeared in the High Court at Gisborne yesterday, assisted by Auckland drink-drive specialist lawyer Zahir Mohamed.
In a hearing that took more than an hour, Justice Murray Gilbert pressed the defence duo to identify the evidence of actual consequences for Mullany that they believed Judge Adeane had overlooked.
Mrs Insley said the time and investment Mullany put into her sport was equivalent to that for which young people studying at university for professional careers were sometimes given such reprieves.
Mullany's participation in such high-level sport was important to New Zealand and brought much enjoyment to New Zealanders.
She might be selected for the 2015 Polocrosse World Cup, which might be held in Canada - a country that would prohibit her from entering with a drink-drive conviction.
Mrs Insley also drew attention to comments in an affidavit-type email from Mullany's former employer. In it, the employer said Mullany was a highly-regarded polo horse groom but her prospects might be affected by a conviction. It could stop her from being able to enter some countries where horses in her care might be sent for overseas competitions.
People of high standing in society, who participated in the sport, might be distrusting of someone with such a conviction and therefore might not hire her.
Crown solicitor Kim Laurenson said the forecast consequences were purely speculative. The information on which they were based was not authoritative enough for a court proceeding.
Information regarding entry criteria for Canada had been downloaded from Wikipedia when it should have more appropriately come, for instance, in the form of an affidavit from a consulate official.
Justice Gilbert reserved his decision.