The Spanish Memorandum by Guy Southwick

In Christmas 1936, the Falchion family is entertaining a houseful of fascist sympathisers, golddigging women, bright young things and bewildered old buffers. The party goes badly wrong when a guest is found murdered and secret files are stolen. The Police, British Intelligence and a lady sleuth are all on the trail - but things are rarely what they seem at Synburn Priory.