fernie, I also can't fully parse 15d.
Despite getting them, I couldn't parse 16d, 19d or 2d until I came on here, so many thanks for the explanations. 16 very clever. 19d not quite fair, imo, as it's the American spelling of nightwear.
Due to (my own) confusion over the spelling of 27a, I only just realised the homophone element of it, and the purpose of the first two words!
Not seen 'harry' as an anagram indicator before (7d)
All in all, a great crossword. Enjoyed 12a, when I finally twigged it!