1: Plantation divided by one true sign of trouble (4,5)
2: Drug problem for 100, in sum (9)
4: Irish playwright livin soundly (5)
5: Heard Italian city in canyon is from the stone age, perhaps (3-6)
6: Again send out note describing Susie misbehaving (7)
7: Top class English under rising roof cover (5)
8: There was little space in the satanic heresy. (5)
14: Hornblower found a strange dog hidden by a hill (9)
15: Unstained slip covers (9)
16: Simple addition in cult film (4,5)
18: Record unusually green ornamental centrepiece (7)
19: Ms. Turner returned to Club Street shrink (7)
20: Confines for periods of time after onset of chickenpox (5)
21: 20-across Love to be a boy on a farm; its a means of reconciliation (5,6)
22: Calculated average time (5)