ANNOUNCING the National Concert Hall's 15th anniversary celebrations last month, new NCH chairman Dermot Egan was careful to credit the outgoing board plans that had been put in place. He may well have been thinking of what happened five years ago, when an incoming NCH board chose to distance itself from the large programme it inherited from its predecessors, even going as far as pulling out of a scheduled appearance by the London Philharmonic under Bryden Thomson. The 1991 legacy, admittedly, with two concerts each from the Czech Philharmonic and Scottish Chamber Orchestras and one by the NDR SO, was far greater than the one inherited by the current board.