Complex sentence: McCall was a key figure in the avant-garde London Film-makers Co-operative in the 1970s and his earliest films are documents of outdoor performances that were notable for their minimal use of the elements, most notably fire.
Split into simpler sentences: McCall was a key figure in the avant-garde London Film-makers Co-operative in the 1970s. His earliest films are documents of outdoor performances that were notable for their minimal use of the elements, most notably fire.