Tickets for the donkeys at the pierhead (6)
I believe the answer is:
passes
'tickets' is the definition.
(pass is a kind of ticket)
'the donkeys at the pierhead' is the wordplay.
'the donkeys' becomes 'asses' (I've seen this before).
'at' says to put letters next to each other (I've seen this in other clues).
'the pierhead' becomes 'p' (head letter of 'pier').
'asses' put after 'p' is 'PASSES'.
'for' acts as a link.
(Other definitions for passes that I've seen before include "Routes through mountains" , "Documents indicating permission" , "Time always does it" , "Moves like mountain gaps" , "'Men seldom make . . . at girls who wear glasses'" .)