Castle mode in the Air by Melville, Alan NEUF

The impecunious owner of a haunted Scottish castle has to juggle the advances of an American heiress who wishes to buy him out, the love of his longtime assistant who wants to marry him, and a Coal Board official who wishes to commandeer the estate. The British National Coal Board wants to annex the owners castle as a group home for local miners and their families. Wealthy, much-married American Mrs. Clodfelter Dunne wants to claim the castle - and its owner, the Earl of Locharne - for herself. Meanwhile, eccentric boarder Miss Nicholson is obsessed with the idea that the mode Earl is actually the rightful King of Scotland.