Possible Clues:

• Where there's very little point to motor to London?
• Shortage to traumatise urban district
• Leave one's mark of the town? Not much! (8)
• Mark urban shortage
• Poverty south Detroit represented thus?
• Short position almost frightening financial centre
• Inadequate supply from Detroit following onset of strike?
• Something uncommon in South Detroit, perhaps
• Inadequate supply from Detroit perhaps following onset of strike?
• Lack vehicle in south London, say