Several titles in Edward Wilson's Catesby series have dropped to $2.99 at Kindle US. When I looked at the rest of the series, I found that several titles are at attractive prices either in the US or the UK, possibly in honor of the 7th book in the series coming out in June. So here goes...
The Envoy, #1, £0.99
Kindle UK:
https://www.amazon.co.uk/Envoy-Cates...dp/B01HSPKJJQ/
The Darkling Spy, #2, $2.99/£1.99
Kindle US:
https://www.amazon.com/Darkling-Spy-...dp/B01HSPKMC0/
Kindle UK:
https://www.amazon.co.uk/Darkling-Sp...dp/B01HSPKMC0/
The Midnight Swimmer, #3, $2.99/£1.99
Kindle US:
https://www.amazon.com/Midnight-Swim...dp/B01HSPKJM8/
Kindle UK:
https://www.amazon.co.uk/Midnight-Sw...dp/B01HSPKJM8/
The Whitehall Mandarin, #4, $2.99/£1.99
Kindle US:
https://www.amazon.com/dp/B01I4AHBCC
Kindle UK:
https://www.amazon.co.uk/Whitehall-M...dp/B01I4AHBCC/
A Very British Ending, #5, $2.99/£1.99
Kindle US:
https://www.amazon.com/Very-British-...dp/B01HSPKJXC/
Kindle UK:
https://www.amazon.co.uk/Very-Britis...dp/B01HSPKJXC/
South Atlantic Requiem, #6, £0.99
Kindle UK:
https://www.amazon.co.uk/South-Atlan...dp/B07B7NF8MW/