I do like the Sloan/Crosby books of Catherine Aird. She is very fair very with her readers-- but sneaky. Most of her books start slowly, a nicely disguised hint here, a crime or two there and as the book progresse, the tension and detection grow faster and faster. Quite a feat! I have read most of her books and cross my heart, I have disccovered the criminal before Sloan only once. Besides, discovering the criminal is not the only pleasure-- the writing and characterization are such joy.
Newcomers to Aird-- I suggest you start at the beginning of the list and work your way through. You will not be disappointed