Complex sentence: He was one of the first post-war English dancers to feature the full natural turn in the Slow Waltz, an innovation which was a factor in his winning the first World Ballroom Dancing Championship in 1922 with Phyllis Clarke as his partner.
Split into simpler sentences: He was one of the first post-war English dancers to feature the full natural turn in the slow waltz. This innovation was a factor in his winning the first World Ballroom Dancing Championship in 1922 with Phyllis Clarke as his partner.