I thought this week was 1ac!
Acronyms again, and I completely agree with Halloway that (1,1,1,1) would be technically more correct than (4). The same goes for the other acronym answer.
I parsed 9ac by taking the “heading to north” (N) from its usual position in the word, and putting it at the end instead. I only solved 18d fairly speedily because we had the same answer for “man-eaters” a month or so ago, albeit with a different clue to get there.
Clue of the day for me was 27ac, beautifully worded and raised a smile.