Possible Clues:

• Steep descent
• Talent for finding underground bar for a quick drop
• Dramatic drop
• Bad news on the stock market
• With these numbers, the editor and I have to take the plunge
• Take the plunge suddenly? No, I have to get around Home Counties date initially
• Hooter goes before dodgy club go into decline
• Go down hill and inquire at local bar with bad reputation
• Devise problem beside number to drop sharply
• Plunge head first