Complex sentence: On 12 September 1916, while No.1 Squadron was still headquartered at Heliopolis, the British began to refer to it as No.67 (Australian) Squadron RFC; this practice continued until January 1918, when the unit officially became known as No.1 Squadron AFC.
Split into simpler sentences: On 12 September 1916, the British began to refer to No.1 Squadron as No.67 (Australian) Squadron RFC. This practice continued until January 1918, when the unit officially became known as No.1 Squadron AFC.