Possible Clues:

• Once ref roughed up by Royal Engineers, impose rule again
• Again impose eco-squad, say, with gallons going to waste
• Implement it again to repel blunder by head of Norwegian police
• It's about small measure for body of people to impose it again
• Impose again
• Make stronger
• Make it operative once more to make it stronger, by the sound of it
• Again compel compliance with (law, rule)
• Refer once to play to emphasise again