Complex sentence: During the 1930s Halls started to produced escalators under licence from a German company, with its products installed in Harrods and Selfridges, among other locations; they continued to make lifts and escalators until 1968 when that part of the business was sold to Otis.
Split into simpler sentences: During the 1930s Halls started to produced escalators under licence from a German company, with its products installed in Harrods and Selfridges, among other locations. They continued to make lifts and escalators until 1968 when that part of the business was sold to Otis.