18d) Back from the Orient, heading off (6) ?????N
20a) Notice Wouk's captain's in swabbing decks with this? (8) ?I?????N??
21d) Cheerful conductor starts wit it (6) ????A?
23d) Hide stone perhaps (4) ??L?
24a) Drink this in Britain with Yankee (6) ????D?
Many thanks in advance for your help.