I wasn’t able to find much to indicate that Gospatric, Lord of Dent and Gospatric, Earl of Northumberland (later Earl of Dunbar) could be one in the same person. The name was unusual but not rare in eleventh-century Yorkshire. I have eight of the name in my own database. The only thing coincidental between Earl Gospatric and Gospatric, Lord of Dent is that both had a son named Dolfin. But according to the above book, Gospatric’s father was named Arkell (apparently a Dane) and Earl Gospatric’s father was Maldred, Lord of Allerdale (of the royal house of Atholl). There is one other possible lead to follow up on. Earl Gospatric’s daughter Matilda was also married to a Dolfin [Scots Peerage, III, p. 245]. I only have three Dolfins in my database and the husband of Matilda is the only one I don’t have a father for. If this turns out to be anything or you have any questions let me know.