Period for deliveries which should get extra? (8)
I believe the answer is:
overtime
'which should get extra?' is the definition.
'period for deliveries' is the wordplay.
'period' becomes 'time' (time is a kind of period**).
'for' means one lot of letters go next to another (I've seen this in other clues).
'deliveries' becomes 'over' (I've seen this before).
'time' put after 'over' is 'OVERTIME'.
(Other definitions for overtime that I've seen before include "Extra hours worked" , "Pay for extra work" , "Work beyond normal hours? Remove it" , "Work outside normal hours" , "Work in excess of fixed period" .)