Some surprising organisations have had to re-learn what they'd forgotten - like desert ops, which Hereford had forgotten before GW1, hence putting in foot patrols into the Iraqi desert, which was a disaster.
Forgotten or ignored?
I was under the impression that B20 went on foot against the advice of the Sqn Cdr and RSM?
Either forgotten or ignored, it was a good example of failure to heed the past resulting in tragedy.