 He remained with this regiment until February 1941.At this time, Cooper had been moved to Płock, near the River Vistula, in Poland.Promoted to SS-Rottenfuhrer, he left the regiment to go to the SS NCO School at Lauenburg in Pomerania, for training which finished in May 1941.

Cooper was then moved to a subunit based at the Dębica training area near Kraków.