I think one Panzer Division would have made all the difference. The UK’s 1940 offensive only had limited objectives, but turned into a massive advance as the Italians were totally unprepared for mobile warfare(or any kind of warfare!).
A Panzer Division could have been spared after the fall of France and the British would have never have advanced as far as they did.
Was not aware one was slated, Worsham. Cannot help you there, sorry.
The 21st Panzer was formed in the field(Summer of 41)from parts of the 3rd Panzer. Its Panzer regiment was the 5th.(The number of PDs were doubled before Barbarossa by halving their tank strength.)
Perhaps that is where you got that idea.