Complex sentence: Clansman was developed by SRDE in the 1960s, and built by Racal and Plessey, it represented a considerable advance over existing radios being offered to the Armed Forces at the time.
Split into simpler sentences: Clansman was developed by SRDE in the 1960s. Built by Racal and Plessey, it represented a considerable advance over existing radios being offered to the Armed Forces at the time.