Complex sentence: Some of the sites such as Balt Moor Wall are of uncertain date; however, the most recent are air traffic control buildings, pillboxes and fighter pens from RAF Culmhead, situated at Churchstanton on the Blackdown Hills.
Split into simpler sentences: Some of the sites such as Balt Moor Wall are of uncertain date. The most recent are air traffic control buildings, pillboxes and fighter pens from RAF Culmhead, situated at Churchstanton on the Blackdown Hills.