Complex sentence: After an immediate post war hiatus, the Army established peacetime anti-aircraft units in 1922 and in 1925 the RAF established a new command, Air Defence of Great Britain, and the Royal Artillery's anti-aircraft units were placed under its command.
Split into simpler sentences: After an immediate post war hiatus, the Army re-established peacetime anti-aircraft units in 1922. In 1925 the RAF established a new command, Air Defence of Great Britain, and the Royal Artillery's anti-aircraft units were placed under its command.