Very grateful for all help with these clues please.
3dn: “Vote in referendum primarily about something negative? (8).”
16dn: “Oscar follows blokes into dodgy bar having left work (4,5).”
17dn: “Philosopher King gets hold of rocket ultimately for space programme (4,4).”
18dn: “Crazy golf followed by bumpy mule ride (3,5).”
24dn: “Exercise set: one’s somersaulting (3-2).”