1: Observed no Knight (5)
2: Quiet floor decoration is a sign of indifference (5)
3: Inspects old radical for a moment (5, 6)
4: Witty remark, for example, about constant batterer (7)
5: Immerse in massive sound (7)
6: Mann's 'Death in Venice' Dorothy sent up (3)
7: Give a bad review to Pain in style (7)
8: Meat and drink kept as refreshment? (4,5)
12: Cereal vermin seized by superb 16-down (11)
13: Accent on three feet as a place of rest? (9)
14: Carol goes round Royal Botanic Gardens, taking an oblique course (7)
15: Tavern drink for the auditor, one with access to confidential information (7)
16: Half of them should have had an idea (7)
19: Frost over mid-January during epic exploit (3,2)
20: Bouquets of flowers, freshly opened (5)
22: No one told sister (3)