8a) Ingredient for cakes, large number outside (5) . Sorry no letters
16a) Spooky peacekeepers getting shrewd (7) ?n?a???
20a) Organise a panto, clue is fruit(10)?a???l???e
4d) Shellfish left in river (4) ???l
5d) Countdown expert dispatched, but is due to turn in (5,4) ???c? d???
17d) Lay another curse to grip the French(7) ?e???a?
21d) Hundred watt in settlement (4) ??w?