I used the expression 'fictionalised account' advisedly, to emphasise the fact that Dahl's story is not, and was not intended to be, a plain, factual account, but rather, a good story.  Based as it was on his interview with Butcher, is clearly broadly factually accurate, but the author was a journalist and novelist, not an historian, and the presentation of the story is coloured by artistic licence, with very boldly characterised individuals.  All these issues are discussed in some detail in the two papers by Hobbs which are cited.  In spite of Dahl's early publication of the story, there is still much that is, and will remain, unknown about the details of the discovery — which is the usual state of affairs with treasure finds.