1 down. Shelf (anag.). 5 letters.
2 down. Customary. 5 letters.
3 down. Pre-eminent – in exemplary fashion. 3 letters and 10 letters.
4 down. Frustrate. 6 letters.
5 down. Potable liquid. 8 letters and 5 letters.
6 down. Wheedle. 6 letters.
7 down. Card game – with odd numbers? 6 letters.
12 down. Reflection you can hear. 4 letters.
14 down. Spaniel sound? 4 letters.
15 down. Energetic type. 6 letters.
16 down. Now rad (anag.). 6 letters.
17 down. Dig down. 6 letters.
19 down. Holiday island. 5 letters.
20 down. Offbeat – cleaving off in layers. 5 letters.