Hi there, stuck on a few clues:
20 Across: Ancient Civilisation I can disclose. (4)
1 Down: Amends made on exposing a rare point. (10)
16 Down: So staged, as I'd dreamt about. (10)
19 Down: They'd come after the movie before coming before it now! (8)
23 Down: d----R (6)
26 Down/27 Across: You can drink or drive yourself to it! (4,3,5)