No further questions from either Auckland Crown solicitor Alysha McClintock or defence lawyer Ron Mansfield KC. Mechanical engineer Andrew McGregor is free to go.

Mansfield tells the court he has a witness ready to go, who has travelled here and whose evidence is set to be very short.

Mansfield has called Regina Gay Haysom.

Mansfield is leading her evidence.

Haysom lives in Ōrere Point near Auckland's southern border, on the entrance to the Firth of Thames.

She used to run a business called Body Shots Photography.

In March 2010, Hanna contracted with her business to provide a number of photos of herself for the purposes of a surprise present for her husband? asks Mansfield.

"Yes, that's what the record said," Haysom says.

She attended a shoot and Haysom produced a booklet of photographs.

There were two wall portraits, each more than a metre both horizontally and vertically, and framed, Haysom confirms.

That concludes her evidence-in-chief.

Auckland Crown solicitor Alysha McClintock, in cross-examination, asks Haysom what year the photographs were taken.

It was 2010, Haysom confirms.

No further questions.

Mansfield confirms it was March 2010.

"I think they were all ready by her husband's birthday. I think that was the purpose," Haysom says.

Justice Graham Lang calls it a day. We will resume at 10am tomorrow but the trial will not sit on Thursday.

McClintock's cross-examination is now into suppressed territory again on the mechanics of the method.

Mansfield interjects: "Are we actually going to get to a question which the witness can answer?" before adding that making a submission is not normally allowed in cross-examination.

McClintock says the witness relied entirely on Polkinghorne's police interview, she's just drawing his attention to what Polkinghorne said before asking her question.

Auckland Crown solicitor Alysha McClintock is beginning her cross-examination of mechanical engineer Andrew McGregor.

She asks who was present. It was himself, a model and an assistant, he said. Polkinghorne was at home but wasn't present for the simulation.

"You’ve had to rely entirely on his account of things in order to do what you did?" McClintock asks.

"Yes I did," McGregor says.

McClintock asks if the main issue is whether Hanna could have committed suicide with the rope found at the scene. 

(To recap, police found the rope connected to the balustrade was unable to support much force, and unravelled when pulled by a detective. Defence lawyer Ron Mansfield said it unravelled because Polkinghorne was told by a 111 call-taker to loosen it when he found his wife.)

McGregor says he's not sure he can answer her question.

McClintock says no disrespect, but you're an engineer, and do not have a pathology qualification?

McGregor says that's correct.

He confirms he had to do some research on partial hangings before the simulation.

Were you aware if Hanna had any engineering qualifications? McClintock asks.

He's not.

Were you aware if Hanna did any research like you did on partial hangings? McClintock asks.

No, I'm not sure of that, says McGregor.

But even you as an engineer, understanding angles, weights, things like that, had to do research in order to simulate a partial hanging? McClintock asks.

(McGregor's response is covered by the suppression order).

Were you aware no other witness in the case had seen Hanna how Polkinghorne said she was arranged? McClintock asks.

"I probably did read it, it didn't feature foremost in my considerations," McGregor says.

McClintock says her point is that he really is having to rely on Polkinghorne's account.

No witness, says McClintock, saw Hanna in any other position than lying on the tiles in the landing.

"Were you aware that's the evidence?" she says.

McGregor is not sure, but says he read the account of the attending paramedics.

"I didn't really need to dwell on that in order to conduct my simulations."

The witness, mechanical engineer Andrew McGregor, has reached the point in his evidence where he is describing the findings of his simulations.

To recap, he was asked by the defence to simulate the method Polkinghorne said Hanna used to hang herself at their Remuera home at Upland Rd on the morning of April 5, 2021.

Details of his simulations are suppressed, but Justice Lang has allowed the media to report his findings.

McGregor says his four simulations all generated enough force to cause death, though he wasn't able to say how long it would have taken.

The jury returns for more evidence from Andrew McGregor, the mechanical engineer who conducted a simulation, at the request of the defence, of how Polkinghorne said Hanna hanged herself at their Remuera home. 

Much of his evidence is suppressed, including the mechanics of the simulation, but the Herald will be able to report his findings when they are entered as evidence shortly.

We are taking the afternoon adjournment. The evidence from this witness remains in suppressed territory.

Prosecutor Brian Dickey, formerly the Auckland Crown Solicitor but now practising privately as a barrister, has told the court today is his last day at the trial.

Dickey has a longstanding personal commitment overseas, the jury has heard. 

For the past five-and-a-bit weeks he has sat on the front bench, where the prosecution sit, alongside current Auckland Crown solicitor Alysha McClintock and prosecutor Pip McNabb.

Justice Graham Lang tells the jury this commitment has long been known to the court.

"Ms McClintock will lead alone for the Crown from now on," the judge said.

The Herald's live coverage is taking a break because the evidence being given now was suppressed by Justice Graham Lang this morning on the basis that its publication could endanger people's safety.

It relates to a simulation carried out by mechanical engineer Andrew McGregor, at the request of the defence, to see if the arrangement described by Polkinghorne in his police interview could generate enough force to cause his wife's death by suicide in a partial-suspension hanging.

The Herald is allowed to report the fact of the simulation and its findings when given in evidence.

To recap the evidence already heard today.

Robert John Willis, Polkinghorne’s former accountant, gave lengthy and at times dense evidence of the series of trusts and companies used by the defendant and his wife. 

He said it was a standard sort of arrangement used by people to protect their assets and insulate their properties from the risks inherent in a trading company. 

Polkinghorne was not employed directly by Auckland Eye, instead consulting via a company that was paid by the practice.

Willis said he had identified errors in some of the account statements relied on by police forensic accountant Magaret Skilton.

He had not sought to correct the errors as police never contacted him or asked for a statement, he said. 

Willis said he met with Polkinghorne sometime in 2023 to discuss the Skilton report.

Anne Theresa Millar, who cut and dyed Hanna’s hair at her Remuera salon Headquarters for more than 20 years, said Hanna was always immaculately turned out, kind and generous.

At her last appointment, about two weeks before her death, she was late, which was unusual, the witness said. She also had to rush out because of another work commitment. 

At earlier appointments that year, she was so busy she had to undertake Zoom meetings while waiting with her foils in during the hair-dyeing process, the jury heard.

McGregor confirms he was asked to undertake investigations to see whether a partial hanging such as Polkinghorne described could allow sufficient force to result in her death.

McGregor is now describing how he conducted his simulation, which the Herald is unable to report without breaching the suppression order.

Ron Mansfield KC has called Andrew McGregor.

Aspects of this witness's evidence were suppressed by the trial judge, Justice Graham Lang, earlier today under Section 205(2)(c) of the Criminal Procedure Act.

That section allows evidence to be suppressed if its publication could endanger the safety of any person.

McGregor is a mechanical engineer who is director of Prosolve Ltd, an investigative engineering firm. 

He's a chartered professional engineer and holds a degree from the University of Auckland.

Prosolve's services include forensic and investigative engineering services.

He was instructed by Polkinghorne's legal team to investigate the circumstances of what was said to be a "partial hanging" at the doctor's Upland Rd home, and was provided with a copy of Polkinghorne's police statement.

Justice Lang has suppressed the details of the simulation. 

But he has allowed the media to report the fact of the simulation, and McGregor's findings, once they are given in evidence.

Mansfield asks if it's unusual for accounts to be amended from first drafts to subsequent drafts, referencing the issue/error the witness earlier said he identified and corrected in the accounts.

No, accounts often go through several iterations, says Willis.

After extensive questioning on when dates are created on financial statements in the Xero accounting software, Willis clarifies the Hanna Polkinghorne Trust was unable to be wound up.

"The trust is more or less in limbo," the witness says.

That ends Mansfield's re-examination and Willis, the chartered accountant, is free to go.