Cryptic crossword

ACROSS

1. It will hold plenty of drink, demijohn: add spirit to it (5)

4. Wild for sex appeal to return in Gallic nation endlessly (7)

8. Study endless number at one, on making the shape (13)

10. Drive one out, upsetting huntsman John around ten (5)

11. Birds that don’t fly can make some of them useful (4)

12. The trick is pleasing, while being deprived of an element (4)

16. Superior to a rating that’s over-short (5)

17. The wandering of Reg, ripe for change with the country (13)

19. People in service fret: kin sue, leaders being lost (7)

20. Thus attendance will make one fetch and carry: hop to it! (5)

DOWN

1. The knave, he was taken in by tourist – a murderer (4,3,6)

2. Wasn’t fast where colour was concerned, but otherwise was (3)

3. People about to help over without scoring (6)

4. They are dowdy fops, nothing less: curious to be inside! (6)

5. Takes advantage of one embraced by Valentine, as surrounded (6)

6. ‘In a moment, in the ___ of an eye’ (S Paul) (9)

7. State getting better? (13)

9. King of Hades with puss, embracing right to be rich man (9)

13. The bit of the page not printed may spoil the spirit (6)

14. Force to cut up diamonds (6)

15. Till up, there’s some recompense (6)

18. Lincoln’s place where traveller may find refreshment (3)