Berrett was convicted, following a jury trial, in May 2018 of threatening to destroy property, attempting to pervert the course of justice and two charges of blackmail.
He was sentenced to two years' intensive supervision and 180 hours community work in October 2018.
Evidence at his trial showed in March 2015 Berrett emailed a large number of recipients, including office holders and members of the RSA, journalists and politicians, detailing how he would burn one of their buildings down if they didn't make amends for what they had done.
Berrett also emailed Gauldie twice in April 2015, threatening to sully his name within the art world.
He bombarded police with letters claiming he knew how to make improvised explosive devices, had built a homemade rocket launcher, and described targeting a Parliament building in an attack, it has previously been reported.
Following his arrest and while on bail Berrett emailed the Whanganui Crown Solicitor in May 2016 pondering what it would be like to reach breaking point and suggesting, if he did, the mental health issues could protect him from standing trial, it was reported.
Berrett took his case against the convictions to the Court of Appeal, submitting the Crown failed to prove that he sent each of the four emails that were the subject of the charges.
He argued the Crown had not traced any of the emails to an internet service provider or a particular device that was used to send them.
In November 2019 Berrett's appeal was dismissed, with the court ruling there was more than sufficient evidence for the jury to conclude that he had sent each of the emails.
At a meeting with police and RSA members in March 2015, Berrett didn't deny
sending the email threatening to burn down a building, but commented he did not consider he had made a threat because he had not put a date on it.
When interviewed by police Berrett acknowledged he had sent two emails to Gauldie and implicitly conceded the email to the Crown Solicitor was in his writing style, the ruling said.
In February 2022 Berrett formally requested the Court of Appeal recall its judgment dismissing his appeal.
Berrett contended the police digital forensic expert, who gave evidence at trial, perjured himself by claiming it was "very difficult" to tell if emails were sent from a particular computer if they had been sent using a web browser.
He said IP addresses were readily accessible and only took a few clicks to find.
The Crown solicitor knew this and had denied him natural justice by intentionally misleading the jury into returning a guilty verdict, argued Berrett, who did not give evidence so wasn't able to be cross-examined at his trial.
He wanted both the Crown solicitor and police digital forensic expert charged.
The court ruled recall was not the appropriate response to Berrett's allegations of perjury and he had not met the high threshold required for a judgment to be recalled.
"Berrett's application for recall is essentially an attempted re-run of the trial.
"An application for recall may not be a substitute for a second appeal by leave, or be used to reopen matters which have already been decided and put forward further arguments."
Berrett's appeal was dismissed.
