Many GPs never knew people had firearms , people who could be a risk to themselves and others . This GP in your quote may have had concerns and voiced them . The Police then decides what action is to be takenI believe that the reason for medical reports is because a schizophrenic had a shotgun for several years, enjoyed shooting and never was a threat to anyone.
His GP retired and a new Doctor did not think he should have had a gun so he was reported to the police.
That is when the shit hit the fan and the rest is history.
Like in the case of Mark Saunders , Did his GP know he had applied for a shotgun cert ? He had a 20 year battle with alcohol and also drug use . https://www.bbc.co.uk/news/uk-england-london-11486194
The Police knew about his problems with alcohol , Did they know about the suicidal thoughts ? Probably not .
He then went on to fire the shotgun at other houses and ended up being shot by police .
Quote
By 2005 - three years before his death - Mr Saunders was drinking to excess most nights.
He himself admitted he was "out of control".
Some weeks he would drink the equivalent of four bottles of spirits. That year, he received a police caution for being drunk and disorderly.
In 2006, a psychiatrist examined him and warned that if he did not "abstain completely from all mind-altering substances" he could find himself being killed in a fight.
The other fear, according to medical notes, was that Mr Saunders would commit suicide if a period of depression and an alcohol binge coincided.
Mr Saunders' best friend Alex Booth often saw what happened when it did go wrong.
"He completely lost touch with reality," he said in a statement.
Did any of these people know he had a shotgun ?
At that time the police would ask you to get a report but if the GP did not get back within 21 days it was seen as there was no concerns and the application carried on .
Did he submit a request ? Probably not as he would have know his mental health and other issues would have been brought up and he may not have been given the cert.