Monkton Hadley (Hadley Green) :: TQ2497 Monken Hadley is an ancient country village north of Barnet, it is now a suburban development situated on the very edge of Greater London. The church dates back to the 15th century. Many of the buildings are listed. The village is close to the site of the Battle of Barnet (1471). Part of the village is Hadley Green a local nature reserve.