Zoe Langley-Wathen and Mike Langley will start the two-year challenge on Saturday, October 4, in support of the Dorset and Somerset Air Ambulance. Their expedition, named 'HeadRightOut: One Coast Any Age,' seeks to demonstrate that "adventure has no age limit." Mr Langley hopes to be the oldest person to complete the mainland coast of Great Britain as a thru-hike, in a Guinness World Record attempt. He said: "I'll be 73 when we set off, and my hope is to become the oldest person to walk the coastline of mainland Great Britain in a continuous circuit. The pair will be walking the entire coastline of mainland Britain anticlockwise, starting and finishing at South Haven Point, Studland.