Biathlonman wrote: “Having cavalry give up horses for tanks or armoured cars must have seemed heresy once too.”

One of the tragedies of the First World War was that the gentlemen at Horse Guards did see the tank (a “crazy idea” thought up by, among others, Winston Churchill) as a heresy.
It was never used to its tactical advantage until after the war had ended.
And even then it was the Panzer Korps (more than two decades later) that used it with brutal efficiency to arouse alarm and despondency in France and drive the BEF out at Dunkirk.
Regards,
Mike