1 down. Tropical fruit used in jams and jellies. 5 letters.
2 down. Something valuable. 5 letters.
3 down. Picnicker Stan – terrified (anag). 5-8 letters.
4 down. Scramble using a cipher. 6 letters.
5 down. It’s measured with an arm cuff. 5 letters and 8 letters.
6 down. Tricky question. 6 letters.
7 down. Eastern Mediterranean island. 6 letters.
12 down. Weighty book. 4 letters.
14 down. Discarded bit of banana. 4 letters.
15 down. Insipid, sentimental. 6 letters.
16 down. Play croquet with one. 6 letters.
17 down. Confirm. 6 letters.
19 down. Spanish farewell. 5 letters.
20 down. Pick up (information). 5 letters.