There are a lot of articles written about early machines available from the (British) Computer Conservation Society. The CCS journal is available online at [1]. One article (with a link to a GitHub) discusses making an FPGA version of Colossus.
There are many articles written by people who were involved in early computing in the UK.
There are many articles written by people who were involved in early computing in the UK.
[1] <https://www.computerconservationsociety.org/resurrection.htm>