[adrian_b]

The manual is for the experimental Manchester Mark II, which is very similar to the commercial product derived from it, Ferranti Mark I.

So both the handwritten title about Ferranti Mark I and the typed title about Manchester Mark II are right. Only the name of the PDF file is wrong.

Manchester Mark I had been an earlier and simpler experimental computer, while Ferranti Mark I was a commercial product. It actually was the first commercial electronic computer, with its first delivery a little before UNIVAC I.