Mr Pinkstone said he returned to the doctor five days later to report he was still unwell and was told to return for a review five days later.

On November 5 – 10 days after his head knock – Mr Diamond attended Frankston Hospital complaining of vomiting,headaches and dizziness. But following “long discussion” between specialist emergency doctors,the coroner heard Mr Diamond was released without a brain scan.

“Ultimately he did not undergo any further radiological scans or tests,” Mr Pinkstone said.

Mr Diamond returned to training at Sting Gym in late January 2019 with a clearance form signed by a GP and in early February took part in a “light contact” boxing tournament.

Notes from his gym on February 6 show Mr Diamond was feeling unwell after a run.

“On February 18 he went to work and then the Sting Gym to partake in a pre-planned five-kilometre run. CCTV[later] shows him commence skipping in a ring at Sting Gym,” Mr Pinkstone said.

But at 6.52pm,CCTV footage showed the 18-year-old walk into an outside car park where he collapsed before stumbling back inside. Soon after he was taken to The Alfred via ambulance.

“Emergency surgery to remove pressure on the brain ... was unsuccessful.”

He died on February 21.

Mr Pinkstone said the cause of death was later found to be complications of acute chronic subdural haemorrhage in a setting of martial arts activity. He said a post-mortem found evidence of old and new subdural haemorrhage.

An inquest into Mr Diamond’s death is expected to examine concussion injuries and what treatment he was given.

Slater and Gordon associate Isabelle McCombe said the young man’s family hope an inquest will shed light on the tragic circumstances of his death.

The matter will return to the Coroners Court of Victoria in November.

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