An argument might be made along the lines of "whenever human beings are making decisions cock ups are likely to occur from time to time". In the case of an unexplained death, such as that of Dr Kelly, there is a counter argument in my opinion that such an investigation will be carried out by professional people who should know what they are doing.
A nearly empty bottle is found near the body. Notwithstanding the fact that toxicology tests were being carried out on samples from the body at a very early stage I would have thought that testing the remaining contents of the Evian bottle would have assumed a very high priority.
From Dr Allan's second report dated 18 August 2003 we learn that it isn't until 25 July, that's a week after the body discovery, that Dr Allan receives the decanted water at his lab. Presumably the analysis of this then receives some priority. The statement of 18 August does, to be fair, also deal with other toxicological matters.
However we have Dr Allan delivering his conclusion as to the analysis of the bottle contents on the same day as the Oxfordshire registrar is recording the cause of Dr Kelly's death.
As an aside I wonder how the bottle and its contents were transported from the scene to avoid spillage and contamination. Surely the top would have to be bagged separately and indeed it has a different reference number.