And a few more singletons, all £0.99 unless otherwise indicated...
Robicheaux, next to most recent (2018) in the Dave Robicheaux series by James Lee Burke:
https://www.amazon.co.uk/Robicheaux-...dp/B07572K5B3/
A Talent for Murder, first in Andrew Wilson's series featuring Agatha Christie as the protagonist:
https://www.amazon.co.uk/Talent-Murd...dp/B01FR8HS22/
Death in Shetland Waters, #6 in the Shetland series by Marsali Taylor, £1.49:
https://www.amazon.co.uk/Death-Shetl...dp/B07529Y1XY/
The Beekeeper's Apprentice, first in Laurie R King's Mary Russell/Sherlock Holmes series:
https://www.amazon.co.uk/Beekeepers-...dp/B006WB7JOG/
Prima Facie, a novella in by Ruth Downie's excellent IMO Gaius Petreius Ruso/Tilla series (which I am happy to see since there haven't been any new titles in a while):
https://www.amazon.co.uk/Prima-Facie...dp/B07SH693ZW/
Died in the Wool, about 1/3 of the way through the Inspector Alleyn series by Ngaio Marsh:
https://www.amazon.co.uk/Died-Wool-N...dp/B003062GOE/
Bones Never Lie, #17 in the Temperance Brennan series by Kathy Reichs:
https://www.amazon.co.uk/Bones-Never...dp/B00I3DNTTU/
Service of All the Dead, Inspector Morse #4, by Colin Dexter:
https://www.amazon.co.uk/Service-Dea...dp/B003GK212Q/
Never Go Back, third in Robert Goddard's Harry Barnett series:
https://www.amazon.co.uk/Never-Go-Ba...dp/B0031RS72W/
Murder in Venice, first in the Venice series by Maria Luisa Minarelli (I had a chance to read an ARC of this and liked it):
https://www.amazon.co.uk/Murder-Veni...dp/B07PQQQX4X/