Complex sentence: In 1951 Watson sold the lease to former Sydney solo rider and speedcar driver of the 1930s, Alf Shields, who had moved his family to Adelaide; during his time as promoter, Shields also regularly drove speedcars at his own track.
Split into simpler sentences: In 1951 Watson sold the lease to former Sydney solo rider and speedcar driver of the 1930s, Alf Shields, who had moved his family to Adelaide. During his time as promoter, Shields also regularly drove speedcars at his own track.