The Victorian court of appeal has asked the office of public prosecutions if it would “amend its hand” – including on whether a manslaughter charge would be laid – in the event Greg Lynn was retried over the killing of an elderly camper.

Lynn, 59, was found guilty in June last year of murdering grandmother Carol Clay, but was acquitted of murdering her fellow camper and lover, Russell Hill.

The former Jetstar pilot was sentenced to a minimum of 24 years in prison for murdering the 73-year-old. He is seeking to overturn his conviction and sentence.

Lynn’s case returned to the court of appeal on Thursday, in a short hearing mostly dedicated to hearing submissions about his bid for a shorter sentence, should his appeal against his conviction fail.

But the court of appeal judge also told the OPP to make clear whether Lynn would be charged with manslaughter, rather than murder, should his appeal succeed and a retrial be ordered.

They also sought clarity on whether the OPP would seek to use the motive of Lynn killing either Clay or Hill for the slaying of the other, who would have witnessed the death.

Justices Karin Emerton, Phillip Priest and Peter Kidd are hearing the appeal, and asked for the OPP to advise before the end of Thursday about its intentions should a retrial be ordered. Dermot Dann KC, for Lynn, has been given until the end of Friday to respond.

Their judgment has been reserved.

_{Sign up: AU Breaking News email}

Asked by Priest whether he wanted to comment on the advice sought from the OPP about whether it would “amend its hand”, Dann responded: “It’s probably appropriate and safer to wait to hear what the director has to say.”

But he agreed it was the correct course of action, given that if a retrial was ordered it would be “in circumstances where it … is the conduct of the prosecution that has led to the conviction being overturned”.

The justices agreed that if any or multiple of the first two grounds, and possibly the third ground, of Lynn’s appeal succeeded then a retrial could be ordered.

Lynn has argued that a substantial miscarriage of justice occurred on several grounds, including that a “prosecutor has launched a sustained attack on the credibility of [Lynn’s] account, without putting many of the matters that went to make up that attack to [Lynn] when he gave evidence in the trial”. His lawyers also argue that “the approach of the prosecution to the evidence of [firearms expert] Mr Paul Griffiths involved a further serious departure from the rules that govern the fair conduct of criminal trials”.

It’s also agued that “there is an unacceptable risk that the jury travelled down an impermissible pathway in arriving at their guilty verdict as regards the charge of murder involving Mrs Clay”. This ground relies on the fact the prosecution’s case was that Lynn murdered both campers.

Lynn’s account was that he was wrestling with Hill for control of a shotgun when it discharged, shooting Clay. He said Hill died after a subsequent struggle resulted in a knife going into his torso.

During Thursday’s hearing, Priest said while he was not arguing that the sentencing judge erred in considering how Lynn treated the bodies after Hill and Clay died, it was important to consider.

Lynn moved both bodies several times, and set them alight, in a bid to conceal his offending, the court has heard.

“It’s hard to not have a strong visceral reaction to what Mr Lynn did to the bodies,” Priest said.

“I regard what he did to the bodies as being absolutely despicable.

“One must still endeavour to approach that very serious aggravating factor objectively, and not be motivated by one’s subjective reaction to it.”

Kathryn Hamill, for the DPP, said the majority of Lynn’s submissions regarding his sentence referred to his age, and there was nothing to indicate this wasn’t considered when he was sentenced.

She said the sentence fell well within the normal range for murder.