Complex sentence: John "Johnny" Rae is a professional rugby league footballer who played in the 1960s, playing at representative level for Great Britain, and at club level for Bradford Northern, as a, i.e. number 13, during the era of contested scrums.
Split into simpler sentences: John "Johnny" Rae is a former professional rugby league footballer who played in the 1960s. He played at representative level for Great Britain, and at club level for Bradford Northern, as a, i.e. number 13, during the era of contested scrums.