ML 350 stalls at idle - help please

[RodFrog]

Our ML350 has just had high pressure fuel pump and all 6 injectors replaced. It now seems to have an issue with variable rail pressure that has not been convincingly diagnosed.
We are hoping that someone has insights / experience of this issue that is causing the engine to stall at idle (often)

 

[DSM10000]

Incorrectly fitted fuel pipes causing an air leak is possible although this tends to come with extended cranking times.
Were the injectors properly set up and coded?

If this only occurred after the other work then the garage is responsible. Are they a Mercedes specialist?

 

[Jobsworth]

Check they have timed the HP fuel pump correctly