Complex sentence: In his youth John was influenced by Motown and Stax that he heard via his mother and a lot of the over 30s from Settle would leave on a weekend to go to Northern Soul--an influence on John's dance style--nights all over Yorkshire.
Split into simpler sentences: In his youth John was influenced by Motown and Stax that he heard via his mother. Many over 30s from Settle would leave on a weekend to go to Northern Soul nights all over Yorkshire.