Possible Clues:

• Doctor, having provided couple with excess of drugs, may be washed up
• Ash found on the beach?
• Break romance within days, finding stuff washed up
• Possible hazard for small boats did for two, unfortunately
• Flotsam
• Import deal possibly giving source of free fuel?
• Current deal, say, that's floating around
• Washed up pieces of tree
• Timber washed ashore did for two in resort
• Timber washed ashore did for odd pair inside