Complex sentence: A new body was created, the Radio Security Service (RSS), headed by Major J.P.G. Worlledge, who until 1927 had commanded a Wireless Company in Palestine.
Split into simpler sentences: A new body was created, the Radio Security Service (RSS), headed by Major J.P.G. Worlledge. Until 1927, Worlledge had commanded a Wireless Company in Palestine.