Recipes suggest that Tetley, Truman, Younger et al had all were Infusion mashing and sparging around the 1850's for some beers, and chevallier was only introduced in the 1820s and was used for over a century IIRC. The point being, mashing practices changed, but the malt didn't.Well, you said it! Much of the time when Chevallier barley malt was king, much mashing was still done by the old multiple mash system (no sparge) and at much higher temperatures; not "single infusion". And, most importantly, for much longer and probably with much longer periods of mixing ("mashing"!).
And you probably used a dextrin happy yeast, even before adding "I'll eat anything" "Brett".
We weren't always so lazy (says me, the prime example of laziness) as to expect 60 minutes of mash will be enough.
[EDIT: Actually, it had always troubled me that Victorians got lowish FGs from high-temperature mashes, I hadn't considered their Brett infected wooden casks until unthinkingly writing out the above response.]