Complex sentence: Burl has noted that Rempstone Stone Circle is "damaged and overgrown", with Gale adding that "the description and evaluation of this site (is) very difficult" on account of it being "much disturbed".
Split into simpler sentences: Burl has noted that Rempstone Stone Circle is "damaged and overgrown". Similarly, Gale stated that "the description and evaluation of this site (is) very difficult" on account of it being "much disturbed".