Yes, I think it’s very much like the older randos Jan Heine put in his book "The Golden Age of Handbuilt Cycles (I think)." It doesn't make sense that all British riders did not value some of the same attributes as French. Riders of both nations valued long solo rides over natural terrain essentially self-sufficiently, so both would need human comfort, reliability , reasonable machine efficiency, similar power delivery requirements, same anatomical structure (hence similar gearing, braking, seating, and hand/arm ergonomics). The British End to End ride was about 900 miles round trip, and the French had many ways to get a 900 mile route, including the famous Diagonale routes. Which was harder? The French Diagonale could include the Alps and the Pyrennees, with coastal Atlantic, Channel or Mediterranean winds and storms, while the End to End covered all of Scotland, Wales, and the Dales (sorry, that's all I know about difficult British terrain, based on British TV!).

As well, solo long distance riding over roads or circumventing roads, has repeatedly caught on in the USA, in my generation (middle Boomers), those earlier and those later.

So for those of us thinking France was It for Randonneur-style riding since perhaps 1870, it ain’t necessarily so!

Plus I may have read a word or two about long-distance wheeling in the USA, exciting the imagination of Samuel Clemens and frightening horses across the USA, since before 1900.

Any case, the utiity of these laid back geometries was not just discovered, it has been in the bicycle marketplace at least as far back aw the early 1900's.