I have a great uncle in my tree who disappeared from UK records. Turned out he went to NZ alone, as a youngster, after a confusing early life being cared for by various relatives. His anecdotes resulted in scrambled recorded info. The first name he gave for his father was actually his brother's. The first name for his mother was his aunt's (who in fact also had a different surname to his). So his descendants in NZ could not follow his backstory to trace anyone in England. Then DNA came along, and finally it became clear who he was connected to.