See 'Rethinking the Carrock Fell enclosure' by Trevor Pearson and Peter Topping, in "Enclosures in Neolithic Europe", edited by Gill Varndell and Peter Topping, published by Oxbow Books in 2002 (pages 121-7). It includes an interpretative survey and full discussion of the site, and comparison with the likes of Aughertree Fell (also published in the same volume). Is it Neolithic? I'm afraid ultimately only excavation can answer that one.