I'm not sure about the inside story on William Mayne's relations with his publisher, but he was far from being an obscure writer. He was a cult figure in the '60s, and although his career had been in the doldrums for a while it had recently revived with Candlefasts and Cradlefasts, the sequels to his classic Earthfasts. Needless to say, all three are now out of print, along with (as far as I can see) everything else he ever wrote. If it's a tragedy, however, it's one of his own making.