The Secret Lives of Codebreakers and The Secret Life of Bletchley Park are both great reads, both by Sinclair MacKay, and Hodges' Turing biography is fascinating and, as we all know, heartbreaking in the end.
Bletchley wasn't just about Turing, though he certainly deserves his due, and then some. Tommy Flowers, for example, who built Colossus -- or Mavis Batey, who broke a coded message that led to reverse engineering the Enigma.
I highly recommend visiting if you can. Really drove home to me the people aspect of the whole thing, and the somewhat frightening (and yet a tiny bit wistful!) realization that had we all been born a few decades earlier, and taken similar paths through life, Bletchley may well be where many if us spent a good chunk of our years.