I was actually looking for the proper "Enigma" machine, but failed to find it on a card. Likewise, Bletchley Park does not appear to feature in any of the sets of country houses, though it was one, before it became the home of the Government Code and Cypher School in the Second World War. But this card does reference the original "Enigma" machine, and so got the nod.
The reason for this is that one of the first class stamps celebrates William Tutte, for "Codebreaking the Lorenz cipher machine at Bletchley Park". Now the Lorenz machines were not "Enigma"s, but they were used by the Germans, and made in that country by C. Lorenz AG, of Berlin. They were actually quite cunning, as they were devices which attached to a standard teleprinter, so you did not have to carry a machine, only this attachment. And more than that, if you found the attachment, without realising that it fitted to something else, it would have been impossible to make work. Because of this, the Germans felt safe at sending all their most important information by the codes they created, but once they were discovered, and the codes cracked, it gave immense power to the Allied forces.
If you would like to read the full story, head over to Wikipedia/Lorenz Cipher
As for Cardsmiths, they are a new name to me, and probably to you. but their website reveals that they already have an impressive stable of issues, over fifty of them, including many sets related to "pop culture" and entertainment.
They also enjoy producing short run and limited editions of their sets - this card, for example, is in "Crystal Sparkle" - but you can also find it in "iced foil", "rainbow holofoil", and a selection of what are known as "gemstone" cards.