Cryptic crossword No 3,734

Across

1. Climbs aboard space crusts (7)
2. Strain diluted as fiscal measure? (3,3)
3. Country film about pain (5)
4. Time to ask for church - an organised unit (4-5)
5. Barbed, small instrument (5)
6. Stable from depression and fuss (4-2-2)
7. Jackpot! Nan and Zulu wrapped by snake (7)
8. Beer spilt over unknown person in bar (4)
9. Sheds confines without opening (4)
10. Patriot spurs a pure revel (4,6)
11. Sue's got small pens - terrible, but I hope it lasts (8)
12. By chance, leader replaced by Oscar from the west (10)
13. Develop when turn loses leader (6)
14. To copy a teaching assistant is skilful work (7)
15. Writing surface great for computer display (7)
16. Fifty years by ear and times - too soon to tell (5,4)

Down

1. BP and hot water: these turn out to be authorities (3,6,4,2)
2. Raise bungled case near the end (8)
3. Policy on yen is rubbish (5)
4. Paper Nazis seen inside each year (5)
5. Growth with skill (4)
6. The Italian and German aircraft (6)
7. King is in government - on the up (6)
8. Signal broadcast as wave (4)
9. Queens Cross extension (5)
10. Greasy CEO's abuse busted (9)
11. Dismissed and put in oven (5)
12. Smothered journalist holding a thousand and two (8)
13. Patent false hope about future Earth dystopia (6, 2, 3,4 ) (15)
14. Bone found every second in Dublin Bay (4)
15. Swerve some festive errands (4)
16. Diplomat, saint and rook swallowed by killer whale - they're found in the pit (9)