1: Lightened up, taking part in strip-tease dance (5)
3: Irrational number turning his coat into nut (9)
7: Propensities for placing bets about leader of nags (5)
9: Characteristic of old door, mouse. (9)
11: For Proust, life's purpose springs from remembrance of a torn desire (6,5)
13: Pious woman in underground hideaway (3)
15: Changes direction with care, as befits a benefactor. (4, 4, 5)
17: Tint bark clogs to provide foot support (8,5)
20: Frost to cover the cake (3)
21: Barque, for one, is a trio-tutor (5-6)
23: Person pressing a lawsuit torched one reptile? (9)
25: Test limits of sexologist in assignation (5)
26: Put another way, perhaps, clarinet overwhelming harps, somehow (9)
27: Stormy channel discovered? (5)