London Bridge Is Falling Down is the most recent (2021) in Christopher Fowler's Bryant & May/Peculiar Crimes Unit series, other than a 2022 book that appears to not be a mystery, but to rather be kind of a travelogue of London from the POVs of the characters in the series. It has dropped to $2.99 in the US.
Kindle US:
https://www.amazon.com/dp/B08Y8D1VFW
Kindle US/Smile:
https://smile.amazon.com/dp/B08Y8D1VFW
Kobo US:
https://www.kobo.com/us/en/ebook/bry...falling-down-1
And Fowler's
Oranges and Lemons, which is the 17th/18th in the series, deprnding on whether you count a collection of short stories, is going for £0.99 in the UK right now.
Kindle UK:
https://www.amazon.co.uk/dp/B07XSNK1QY
Kindle UK/Smile:
https://smile.amazon.co.uk/dp/B07XSNK1QY