I noticed this detail in the article: “the Witchcraft Act of 1735...clarified that witchcraft itself was not a crime; however, it was illegal to falsely claim to perform witchcraft or fortune telling, recognising that those who practised witchcraft were fraudsters without real magical powers.”
So the 1735 law did not recognize the reality of witchcraft but assumed that witchcraft was a form of fraud !
Apparently the British were planning to keep it a secret until the end of the war, or as long as possible.
But the rumor was already circulating.
The footage of HMS Barham exploding was held from the public until after the war, iirc.