Previous cryptic solution

Across: 1. Patio 4. Shellac 8. Interpolation 10. Sheet

11. Pane 12. Zoic 16. Never 17. Obstetricians 19. Strolls

20. Reply

Down: 1. Principal boys 2. Tut 3. Onrush 4. Spoken

5. Enacts 6. Loincloth 7. Conspicuously 9. Condenser

13. Unwell 14. Averts 15. Grocer 18. Amp