> "The world's fourth digital computer ... 1949 ... CSIR Mark 1 - later renamed CSIRAC"

For anyone else triggered in the same way as me, I think the other three are:

- Colossus 1943–1945 "the world's first programmable, electronic, digital computer" [0]

- ENIAC 1945 "the first programmable, electronic, general-purpose digital computer" [1]

- Manchester Baby 1948 "the first electronic stored-program computer" [2]

[0] https://en.wikipedia.org/wiki/Colossus_computer

[1] https://en.wikipedia.org/wiki/ENIAC

[2] https://en.wikipedia.org/wiki/Manchester_Baby