16A Seamen struggle with it rounding harbour mouth (9) M.I.S.E.S mainstays doesn't fit I make 16D menace, clue is; Threat: foe nearly all turn up,seize a castle, then... I also make 5D sweetness, clue; Confection in tiny teaspoon with steam swirling about. The last letter (s) is the last letter in 16A! Please help! Where have I gone wrong?