Possible Clues:

• Is this where one keeps the sleepers undercover for surveillance on The Doors?
• Keep an eye on those on the golf course - without them you won't see who is approaching the driveway
• Keep an eye on those on the golf course - without them you won't see who is coming up the driveway
• They offer covert views of mole on parts of course
• Agent finishes 12 across with One Direction offering to keep an eye or two on The Doors
• Presumably where one keeps agents out of sight - the ones keeping surveillance on The Doors?
• Secret agent contacts Burrows for surveillance at The Doors?