21A - Wide-ranging alarm about old farm animal (9) ?Y?????I?
26A - Noblewoman aboard English ship on St David's Day (11) ?N????????S
18D - Rising, quote work written in verse (6) ???R??
19D - A success in odd parts of this island (6) ???I??
23D - Dish that is supporting piece of meat (5) ?UT?? (maybe BUTTY)
If so then 21A will finish with a B