IMHO, the ONE potentially relevant factor that this article, and the AAIB updates themselves are completely silent on is the MATERIAL, i.e. the fuel itself, whether it be chemical composition, or physical properties, or additives, or other attributes.
That would not be my interpretation of the AAIB reports.
Special bulletin 3/2008
The fuel has been tested extensively; it is of good quality, in many respects exceeding the appropriate specification, and shows no evidence of contamination or excessive water.
GCMS must have been done to confirm that fuel did not contain any contaminants, for as Pinkman pointed out, the standard Defstan/ASTM tests can only confirm or otherwise that the fuel meets spec. Whereas only GCMS can show whether the fuel consists "Solely of hydrocarbons and approved additives" as it must do and apparently did.