I came across a reference to “a pocket watch made by John Willats in the 1700s” and have been unable to locate any watchmaker or horologist by that name, or any close spelling. The reference is fictional but appears to be intended to refer to a factual item and maker, and the author is given to spelling and other errors in these details.
The will names his father and brother,and is dated 1760; Willats apparently died 1762 and was born ca 1720. There are other possible spellings (Willets? Willis?) but Willats seems to be what he used.
In a Member Tree at Ancestry.com (not necessarily reliable), we find he married Susanna Pow (d 1773), had a son Thomas who m. Julia Ann Kington, and several grandchildren. His parents were William Willats (son of Moses and Constance) and Eleanor Bell. His siblings include Mary, Sarah and Moses.