Related Clues:

• You may need this to get permission to travel round by way of the South
• Pass the half-dozen as it comes back
• The way four is back for permission to come in
• Half a dozen, as it's up for travel (4)
• As one gets five back it lets one in
• Six as it turns to get one in
• Pass this as it turns after six
• American Express rival
• Border-crossing pass
• It can get you credit in a store
• MasterCard competitor
• "Don't leave home without it" card
• Plastic choice
• "Don't leave home without it" card (Abbr.)
• Certain stamp of approval