The doctrine bit is actually the real problem when it comes to the British army in WW2.

The thinking in the 20ies and 30ies plus dwindeling funding led to the dreaded cruiser/infantry tank concept. And this started to rot. Worse was the experiences from operation Compass seemed to reeinforce the sensebility of Independent Armd. Brigades Swanning about. This was going to cost a lot of Tanks for the rest of the war.
Throw the Regimental system into the ring and then you have an unmanagebal situation.

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'We march. The enemy is retreating in transport. We follow on foot.' Lt.Neil McCallum 5/7 Gordons 19th November 1942