In May 1966 Geoffrey was contacted by Michael Dummer, who had started a study of all Dummers, concerning Geoffrey's family history. At that time Geoffrey knew almost nothing of his ancestors before his grandparents, but was stimulated to start researching them. He was particularly hopeful of establishing a link with the notable Dummer family who had held estates in Hampshire in the 15th, 16th and 17th centuries, and who included in their number Edmund Dummer, Surveyor of The Navy, and Richard Dummer, one of the founding fathers of Massachusetts.