For much of the 20th century its name was Lithgows, as it was developed further by William's sons Sir James Lithgow (1883–1952) and Henry Lithgow (1886–1948), and then by his grandson Sir William Lithgow (born 1934).
For most of the past century, the company was referred to as Lithgows. It was expanded upon by William's sons, Sir James and Henry Lithgow, and later by his great-grandson, Sir William Lithgow.