A few most-recent-in-series titles at Kindle UK for good prices...
The Body on the Train, Kate Shackleton #11, 2019, by Frances Brody, £0.99:
https://smile.amazon.co.uk/gp/product/B07QYTRR24
Fear on the Phantom Special, Railway Detective #17, 2019, by Edward Marston, £1.79:
https://smile.amazon.co.uk/gp/product/B07RD4G8GV
Cold Malice, Gunnhildur #7, looks to be the most recent since it was pubbed in 2020, by Quentin Bates, £0.99:
https://smile.amazon.co.uk/gp/product/B07VGQDCW3
And a couple others at nice prices, not most-recent-in-series
The Assassin's Riddle, Brother Athelstan #7, by Paul Doherty, £0.99:
https://smile.amazon.co.uk/gp/product/B0844P8J1K
A Quarter Past Dead, Miss Dimont #3, by TP Fielden, £0.99:
https://smile.amazon.co.uk/gp/product/B07CWVH3WX
As always, to get the non-Smile links, just replace "smile" in the URL with "www"...