9th Infantry Brigade and Brigadier Arthur Orr/22nd Armoured Brigade and Brigadier Harry Jackson

Good day everyone,

I'm currently researching why Anglo-Canadian brigade commanders in 21st Army Group were relieved of command and I've stumbled across a couple of puzzles.

The first is Brigadier Arthur Orr. He took over command of 9th Infantry Brigade after Cunningham was wounded on D-Day. Orr was relieved of command in early August 1944 as Maj. Gen. Whistler's was not happy with him (at least according to his biographer).

The second is Brigadier Harry Mackeson. Mackeson took over from Hinde in early August but only lasted a month before he was fired and replaced by Brigadier Hugh Cracroft (according to then Colonel A.D.R. Wingfield who would later replace Cracroft).

So apart from Whistler's biographer and Wingfield's autobiography, I can't find anything that would suggest a reason why these two men were fired. Both seemed to have won most or all of the battles they fought (I'm happy to be corrected if this is wrong).

Anyone have an insight (i.e., evidence that can be used in a PhD dissertation) into why these two men were fired?