1: Three kernels of copper-yellow grain (3)
2: Expel the ones who show up (7)
3: Sounds like actor Stephen's a scavenger (7)
4: Hungarian composer on CD extra, perhaps, with Norwegian composer (7)
6: A sign of winter here in Paris -- clashes when ash is dumped (7)
7: Employ heart-broken Spartans where disaster came to pass. (11)
9: Whip stuff with energy (5)
11: Rifles protect lady from 16-down overhead (11)
14: Private entrance in back behind Post Office (7)
15: Col in unopened 10-across tie (7)
16: Personal belief: IPO in no trouble (7)
17: Propane explodes, theoretically (2,5)
18: Wooded hillock forming part of Arthur's territory (5)
19: Decisive curl twisting around spy body (7)
25: Looks like an eyesore, sounds like an eyesore (3)