I don't have an Ellen, there were a few branches of the Pegg's in Derby by 1800. Several had been there for a long time (Tudor horse traders) the focus seems to have been Littleover and Mickleover.
I do have a James Pegg born 1760 in Mickleover, a potental candidate for the father you are looking for? I'm from his brother John's (b 1752)line. If you link I can take you back 4 more generations, an potentially a lot more.
Most Pegg's seem to ultimately have roots in the Ashbourne area.