The Bletchley Circle series is more Downton Abbey than Imagination Game. A lot like Numbers in the way characters pause mid- procedural to explain a code breaking concept, the Bletchley circle series center on a group of women (amateur) crime investigators who formerly worked at Bletchley Park. The first series is 3 episodes and one case. The second series has 4 episodes split between two cases. Both series are set in London and are available on PBS streaming or DVD/Blu-ray. The newest series is set in San Francisco. Some of the original cast returns. This 8-episode series came out in July of this year and can be streamed on Brit-Box.
There are many nods to WWII era code breaking techniques and the machines of the era. The original two series pre-date the Hidden Figures phenomenon. These are a quick binge for those who like the procedural genre with a little math thrown in. A more serious treatment of women at Bletchley can be found in the book The Bletchley Girls, by Tessa Dunlop
For a book on women code breakers during WWII in the United States try Code Girls: The Untold Story of the American Women Code Breakers of World War II, by Liza Mundy