Related Clues:

• See 23-Across
• See 34-Across
• Edges
• Dispute subjects, perhaps
• Sites for skirmishes
• Perimeters
• Big bookseller
• Outer boundaries
• Margins
• Checkpoint sites
• Customs Service posts
• Boundary lines
• Sites of some clashes
• Bygone bookstore chain
• People getting on, we hear, in southern Scotland