Possible Clues:

• Green veg not quite cooked - a dish best served cold
• Ship remembered in verse as example, at no stage given up
• A 3 a 2 they say?
• Forgetting one's own back?
• Crime motive
• Around five, could there be a green E. to make it sweet, as they say
• Whodunit plot device
• 1990 film starring Kevin Costner
• Taxmen waiting at last for upper-class retaliation
• Eye for an eye, so to speak