Willoughby Bertie was the third Earl of Abingdon and a major eighteenth-century landowner. He is identified as the Bertie holder who sold Aldworth Manor in 1756.

The manor sale is the direct evidence for his connection with Aldworth.

Research sources:
- Kelly's Directory of Berkshire, 1899, Aldworth entry, quoting the historical descent of the manor. — https://forebears.io/england/berkshire/aldworth