The Coroner is not bound to investigate. Direction given by the Lord Chief Justice after the Norfolk Coroner demanded the CVFDR from a helicopter accident (same sitting as West Sussex police wanting the AAIB’s Shoreham witness statements), was that Coroners should only conduct their own investigation if they had evidence that the specialist investigation was fundamentally flawed or incomplete.
Whatever your views on the independence of the DAIB, I don’t think you could make a legally defensible argument that the SI was fundamentally flawed in its conduct or conclusions, or that it was incomplete.
The coroner will determine the cause of death, which is outside the ToR for the SI. He may also call the ODH for justification of the ALARP safety statement. Also, inquests are Article 2 compliant, SIs are not.
DV