I’ve been in Norway all weekend (and up in the fjords out of range for much of it), so didn’t have access to the grid until I came here this evening (thanks so much, jono), having solved all the clues, not without a struggle. Can’t remember what my FOI was (possibly the strangely straightforward N). LOI K as I knew neither the currency nor the ‘big gun,’ so I started with the other element and found a four-letter currency beginning with K (the obvious 5-letter ones being equally obviously unworkable).
COD, and the penultimate entry: G.