Now that publicity has become more of an industry than an art, most ­theatre productions can be seen ­coming from a long way off. Just before ­starting this piece, I opened a National Theatre email alerting me to a David Byrne and Fatboy Slim musical in October and a December adaptation of Treasure Island. So the ­production that opened at the National on Monday night is highly unusual in having been announced only 72 hours before the ­premiere and – a second distinction – starting directly with a press night rather then the usual run of fine-tuning previews.The reason for the stealth marketing was legal. Richard Bean – who previously gave the NT one of its most controversial productions with the immigration play England People Very Nice and one of it