I'm putting this up as a hopefully thought-provoking question.
If, as I conclude, the "suicide hypothesis" looks at best problematic and, very likely, is discredited what is the correct explanation of the "death of Dr. David Kelly"?
The possibilities of natural causes and accidental death don't, in my view, merit serious or lengthy consideration.
It follows, however, that if it's not suicide, not natural causes and not accidental death then it has to be murder.
I can identify no other option. Can you?
If it's murder, then it's not a casual murder. It's not a simple mugging, for example.
If it's murder dressed up as suicide, what could the motive be?
Meantime, I'll leave that as an open and unanswered question.
If it's murder, then the question of motive requires a credible answer.