17 across Greeting commonly heard from sentinel(7) ??T???R
13 across Moving stealthily, Lila goes off to moon (6) ??T???
14 across Extreme examples of generosity (4) ?I?S
^^^ I'm rubbish at cryptics, Syruphead, but (as I see it) "Greeting commonly heard' translates as "this sounds like a greeting". So the actual answer is 'watcher'