Here's your list of all the Agatha Raisin books in order, which ones the TV show has covered and what was changed.
Agatha Raisin Series in Order
Agatha Raisin, Agatharaisin Wikia
Romance, Mystery, and More: 14 Royally Delightful M.C. Beaton Books
As The Pig Turns (Agatha Raisin) by Beaton M C
Search Results for agatha raisin Agatha raisin, Cozy mystery books, Mystery books
M. C. Beaton - UK fans: Have you been enjoying Agatha Raisin Series 3 on Sky One? Tune in tonight at 9 pm for the final episode, As the Pig Turns!
Agatha Raisin (TV series) - Wikipedia
Kittling: Books: While Miz Kittling Knits: Agatha Raisin
Agatha Raisin- Series 3, A Review – Ramblings of a Supposed Writer
Agatha Raisin Books In Order: All 36 Books By M.C. Beaton
Agatha Raisin: As the Pig Turns (book), Agatharaisin Wikia
Agatha Raisin and the Fairies of Fryfam book by M.C. Beaton
Death of a Maid by M. C. Beaton
Agatha Raisin - Series 4 (+The Christmas Special) (2 DVDs)