Re 16a, I agree with Bowergirl that it's an unfair clue as To is a word in it's own right and there is nothing to indicate that it's a truncated word. Only got it with the crossers, and even then wasn't initially sure.
If you've not already got it HeleninGlos, 'to' is a shortened version of a male feline, which has a shortened tail (so the word is 'de-tailed'). Clever in retrospect, but not a good clue for the likes of most Everyman solvers (like me!)
7d is the name of a well known animal (from the clue) with the first 3 letters parsing as a homophone for main (think marine) and the last 7 parsing as something you might snack on for elevenses.