1: A drain could be at the bottom (5)
4: Civil libertarian sends building uprights (4,5)
9: How to get around doing business, essentially (3)
10: They can't reproduce sounds like an operating system (7)
11: You audibly ram partner (3)
14: Poker-faced piper who has passed away (7)
17: Some native general back in the desert (5)
20: Put a new value on what secret agent is hiding (5)
21: At sea I reused what's left (7)
22: Fancied poem composed in comfort (5,2,4)
26: Bloody bored inside (3)
27: Right, turn right to play with robot (3)
28: Cut out ad about folding table (7)
29: Clothilda is carrying a parcel (3)
30: Suspicious nag, roused, is apt to make trouble (9)
31: Antelope found in oriental country.(5