I received a copy of a will yesterday of an Edmund Jacklyn, lighterman of St Dunstans, London who died in 1810. He left property and money to Mary Jacklyn otherwise Smithers who had lived and resided with him for many years. I also mentions Mary's 5 children Edmund, Joseph, Richard, John and Sarah. All known as Jacklyn otherwise Smithers. I don't know if these are Edmund senior's children. There is no Rebecca but wondered if there might be a connection to the families you are looking for. I know it's a long shot. Have you found out any more of your Jacklyn/Smithers?