Possible Clues:

• Welsh cocoa's no source of energy; it could make someone sluggish
• Person (or transport?) taking a long time
• Sven in customary relaxed mode!
• Was cool dancing companion one inclined to dally?
• Tortoise-like walker
• Sea fish circling can circle snail
• Dunce gets finally to not very elevated stage
• Not a fast worker
• One who lacks liveliness, like old vehicle
• Long-delayed passenger vehicle, not one of the fleet