Complex sentence: The Colne Brook splits off as a distributary between New Denham and Uxbridge, after this at West Drayton the Frays River rejoins and the Wraysbury River and Duke of Northumberland's River divide off.
Split into simpler sentences: The Colne Brook splits off as a distributary between New Denham and Uxbridge. After this, at West Drayton, the Frays River rejoins and the Wraysbury River and Duke of Northumberland's River divide off.