Sewardstone

From the longer Wikipedia page

Sewardstone is a hamlet in the civil parish of Waltham Abbey, in the Epping Forest District of Essex, England. It is 11.6 miles north-northeast of Central London and is in the London commuter belt.

The area has scattered development, with large sections of open land. It is centred on the A112 road (Sewardstone Road), which connects Waltham Abbey and Chingford. The King George V Reservoir and Sewardstone Marsh form the boundary with the London Borough of Enfield, to the west. It is connected to Enfield Island Village by a footpath but not by road. A section of woodland forms the boundary with the London Borough of Waltham Forest to the south. To the east is High Beach.

It is the only place not in Greater London to have a London postcode (E4).

The headquarters of the world Scout movement, Gilwell Park, is in Sewardstone.