My great grandmother appeared on a family tree prepared by a distant cousin as Louisa Knapman, which was odd because my mother was convinced he name was Satchell. When we came to investigate the marriage cert. definitely said Knapman and one of the witnesses was John Satchell. A Louisa Satchell had been born in Newport (where we knew she came from) 17 years before and appeared in the censuses along with her brother John but never married, died or appeared in later censuses. Likewise no sign of any Louisa Knapman except for this marriage. Assumption was that the marriage, in London, was without parental Knowledge. I've been told on here that despite the incorrect info. so long as banns were read, which they were, and no one objected the marriage was perfectly legal.