Wicked Autumn by G.M. Malliet

Wanda Batton-Smythe runs Nether Monkslip's Women's Institute with an iron hand, so it's not so surprising that she's found dead in the village hall during the Harvest Fayre. While allergic to nuts, it seems she's been poisoned by them. The local vicar, Max Tudor, formerly with MI5, is asked by the local police to assist them in their inquiries. Max, knowing the residents of his small village well, finds it hard to believe that one could be a murderer, but questions them, nonetheless. With details of English small town life and its inhabitants, Malliet has written a read-alike for readers of Caroline Graham, M.C. Beaton, and Rhys Bowen's Evan Evans series.