I wouldn't be so quick to say British just from the tubes being inch-based dimensions and Eng./ISO BB threads. Lots of bikes from other parts of the world used those too. Almost everywhere other than Italy and France.

Your revised numbers still contain some typos, I believe at least three, can you doublecheck?
25.2 mm is under 1", not 1.08".
You got 28.9 mm for both DT and ST but got different inch conversions?
Your ST is not likely to be 1.35", that's over 34 mm.