The 4th Armoured Brigade was training, in early October 1941, in "the barren spaces west of the Cario-Fayoum road". Robert Crisp says that they were having "battle-practice with live ammunition". He says that they thought that the German 88mm gun could hit a tank at 3,000 yards, while they had the 37mm pop gun that could only reach about 1,200 yards. He says that in fact, they found that the effective range of both the 2pdr and 37mm guns was much less than the 1,200 yards that they had been told.
Robert Crisp had an idea that he wanted to try, to see if he might be able to get close enough to fire without being knocked out. He figured that he would not be able to fire from a moving tank, so he thought that if he could use the mobility of the tanks in his troop to close with the enemy. His idea, which I know is sound, was to have his gunner keep his sight on the target while moving, and when the tank stopped, the gunner would fire. This was to be an automatic procedure, happening without any further orders. Experience in battle practice indicated that this idea could work.
This is based on the account in Robert Crisp's book, Brazen Chariots.