Possible Clues:

• Surveillance
• Kate's put under surveillance
• Police operation ... or, when read another way, what a grammarian would like to do to 18-, 24-, 52- and 65-Across?
• Watch, as a criminals' hiding spot
• Seconds to destroy place under surveillance
• *Police surveillance
• Post elsewhere for police job
• Head of security has to remove surveillance
• Sounds like something that was said during foot-and-mouth crisis concerns police doing a bit of undercover work
• Police operation requiring patience