Stuck on last three.
3d. Hamlet's soft-footed thunderer (5)
??o?p
15d. Inferior-an example being Rosinante(3.5)
?n? horse. This refers to Don Quixote's broken down horse, I am sure the N is correct.
1a. Coloured glass in mid-Wales in a most shattered state leading to...(6)
S?A??? penultimate letter is the first in 3d