Chew Valley Hoard Fiasco: Time Discrepancy

I have already drawn attention to the aspect of 'numbers' in the ongoing Chew Valley Hoard Fiasco, nobody can get the number of coins right. There is also a huge time discrepancy. By law, the finders have 14 days to report potential Treasure. In this case, "all" the coins were in the British Museum the day after they were hastily hoiked from the ground in a raging rainstorm. Yet it took seven whole months for the public to learn that part of the archaeological heritage was above-ground. Since it all about getting knowledge of 'Treasure' finds in the public domain, why does the Treasure Act place all of the obligations on the finder to report to the authorities representing the public interest, but zero obligations on those authorities equally quickly to inform the public, in the same public interest?

Why do the BM and Coroner feel empowered to sit on this information, hiding it from the public, and even when that information is made public, hiding part of it from the public? We expect transparency from finders, where is that reciprocated in what the 'authorities' do?