That was hard work: until starting to read this thread we had only half a dozen answers, but with all your help, and resorting to the "crossword solver" when I had 4 Crossers for 8a but still no idea which "tongue", we've now completed. Phew.
FOI 5d, LOI 8a, COD: probably agree on 15, though even with 3 crossers I didn't get it until offered "versus" - small but perfectly formed.