In the 'Service Areas' tab, you'll find a section called 'Travel Preferences' by scrolling down past the category tick boxes.
Adding a New Location
To add a new location begin typing your postcode or the name of your town into the box marked 'Service City or Postcode' and select an option from the drop-down list. To the right, you'll see a box labeled 'Distance' select this and choose your desired radius.
Once you are happy with you selections simply click the green 'Add Location' button to the right to add your new area to the chosen locations below.