I have always assumed that this is the castle of Dromore in County Tyrone - between Omagh and Enniskillen (which is in Fermanagh. There certainly is a ruined castle which overlooks the village. There are, however, other Dromores, one in Co Down, near Banbridge between Belfast and Newry, and presumably one in Kerry. Which one Harold Boulton had in mind may not be known - does anyone have biographical knowledge?