2: Piano finale not determined (7)
3: Old physician in sheltered church (5)
4: Spout off, immersed in Homer, to quick-tempered person (7)
5: Dilapidated sofa contained initially some hot embers: something's burnt remains. (5, 2)
6: Moderately amphibian, for example, by the middle of the creek (2,1,6)
7: The last movement produces great passion (7)
8: Think at length about lost planet, comet (11)
10: Fashion term heartless: Feeling up Blossom (6-2-3)
14: Massive dinosaur hiding in Antigua? No, Donna! (9)
16: Climactic age opal tossed (7)
17: Caught sight of leaderless French church embracing a politician. (7)
18: Feet of people who get talked about (7)
19: Americans look for no revolution (7)
21: Links to some 7-down (5)