Complex sentence: John Massey is a professional rugby league footballer who played in the 1950s, playing at club level for Warrington (Heritage № 575), as a, i.e. number 6 or 7.
Split into simpler sentences: John Massey is a former professional rugby league footballer who played in the 1950s. He played at club level for Warrington (Heritage № 575), as a, i.e. number 6 or 7.