Four early-ish titles in the John Cunningham/Three Oaks series by Gerald Hammond are on Kindle Countdown at both Kindle US and UK, for $0.99 and £0.99 each, respectively. If you're interested, you'll need to evaluate how patient you are - many Endeavour Media titles go free from time-to-time, but rarely, and for a brief time when they do. So you can grab these on Countdown, or wait for free...

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Titles (great titles in this series, BTW, IMO) are:
- Doghouse, #3
- The Curse of the Cockers, #5
- Sting in the Tail, #6
- Mad Dogs and Scotsmen, #7
In addition, the first title in the series,
Dog in the Dark, is long-term at $0.99 and £0.99 if you want to try the first in the series first. The links pull up all five, except for the Kindle US link for some reason doesn't snag
Dog in the Dark, so it's listed separately.
Kindle US:
http://www.amazon.com/gp/search/?sea...9&keyword=oaks
Kindle US,
Dog in the Dark:
https://www.amazon.com/gp/product/B07QM5XY51/
Kindle UK:
http://www.amazon.co.uk/gp/search/?s...9&keyword=oaks
Oh yeah, on Countdown for about 4 3/4 more days...