Grahamr, I think your reasoning is correct. I’d come to the same conclusion about that clue.
Please can someone explain the parsing of 27a?
Posy suggesting one’s head not all straight? (7)
The answer looks like NOSEGAY (= posy). Where does the NOSE bit come from? I can see that it’s an anagram of ONES, but what does that have to do with “head”?