original: In the 1920s and early 1930s he frequently worked with the London Symphony Orchestra.
simplifications: In the 1920s and 1930s he often worked with the London Symphony Orchestra. In the 1920's - 1930's he worked with London Symphony Orchestra. He worked with the London Symphony Orchestra in the 1920s and 1930s. In the 1920s and early 1930s, he often worked with the London Symphony Orchestra. He often worked with the London Symphony Orchestra in the 1920s and early 1930s. In the 1920s and 1930s, he often worked with the London Symphony Orchestra. He frequently worked with the London Symphony Orchestra in the 1920's and 1930's. He worked with the London Symphony Orchestra in the 1920s and earky 1930s. In the 1920s and early 1930s he worked with the London Symphony Orchestra all the time. He often worked with the London Symphony Orchestra in the 1920s and early 1930s.