Complex sentence: One combined a mandolin and a guitar (along with four bass strings operated with slides), the other combined guitar and the Spanish bandurria, the latter being an instrument Williamson had played since the early days of the Corrie Folk Trio.
Split into simpler sentences: One combined a mandolin and a guitar (along with four bass strings operated with slides), the other combining guitar and the Spanish bandurria. The latter was an instrument Williamson had played since the early days of the Corrie Folk Trio.