Possible Clues:

• Close friend in Grenadier Guards
• Awaiting decision with no introduction or conclusion
• That'll make it last
• Last part
• Bad thing to give away
• Conclusion ... or, in three parts, what four answers in this puzzle unexpectedly do
• Outcome
• In conclusion, it's the ultimate gin cocktail
• Not quite over being wound up
• Last for the last of 35 across