Finished, after helpful clues from this forum, not least a nudge to the right kind of "wrap": I was thinking of street food! And I needed the clue about the opponents in 6d, after which I cracked 8a, 4d, and then my LOI16a.
17a's clue was a familiar word though more frequent as "inter....al".
FOI was 20d. COD: perhaps 2d, though I solved it as an anagram without using the clever re-parsing of 19d!