Clue: No more fencing for camp men about to retire? (4,4)
Answer: LAST POST
Explanation: Definition: camp men about to retire
If you've reached your LAST POST then you can't put up any more of your fence. This bugle call is probably best known to most people from its use at Remebrance Day, but it's also the signal for the end of the day in an army camp, so time to "retire"