The problem with discussing the subject of the death of Max Spiers is that different sources say different things, and one can't really know what is rumour and what is fact or at least not as far from fact. (Before either the British inquest or Polish investigation conclude.)

Your source says that Duval wouldn't allow Mr Spiers' body to be taken from her place by either police or doctor.

The source I came across originally seemed to say the opposite - that both dr and police would not remove Mr Spiers' body despite Ms Duval's requests to.
I think it was suggested the police first actually refused to take Max's body anywhere, as they needed a medic initally. I'm not sure if Mr Spiers would have been dead at the point, or long dead.
I understood the police could not initially decide that a crime was involved. I think that can prevent them removing the body, by law - to morgue. As they were satisified the dr was coming or present, I suppose they had no further responsibility to move the body to a hospital.

I believe the dr could not resuscitate Max, after which, the body ceased to be his responsibility and he refused to move the body, despite Ms Duval's requests.
Possibly some exchange ocurred between dr and police, where what the dr said to the police still would not lead them to decide a crime had taken place.
That being so, it may be that the body was left until investigators could attend on a non-urgent basis.
My understanding from the source was that Ms Duval pleaded with both to take the body and thought for some time he may be resuscitated.
She may have been in shock.

But I have no idea which source and which story is correct, or the more correct. I suggest that is the same position most people are in - people who's sources of the death of Mr Spiers are general press and internet reports are all in this position.