Yes, I had always assumed that Joseph was bap 1769 s Joseph and Ellen but hadn't thought about the Scottish naming system (I didn't know it was used so far south). The mothers' names fit well, but naming your first three sons William, Philip and then Joseph seems odd unless there had been some earlier children who died.
Ellen appears to have had at least seventeen children spread across thirty years, but I think I'll focus on finding the Joseph/Mary marriage (if, indeed, they married).
If Joseph (b1769) and Mary BAYLEY (b1767) are the right people, they are quite old when they start having children in Dilhorne, so perhaps there were earlier children (or other marriages).
Richard