Designer needs pen and catalogue (7)
I believe the answer is:
stylist
'designer' is the definition.
(I've seen this before)
'pen and catalogue' is the wordplay.
'pen' becomes 'sty' (both can mean an animal enclosure).
'and' is a charade indicator (letters next to each other).
'catalogue' becomes 'list' (a catalogue is a list of items).
'sty'+'list'='STYLIST'
'needs' acts as a link.
(Other definitions for stylist that I've seen before include "Designer of fashionable clothing" , "Good writer" , "coiffeur" , "Clothes designer; hairdresser" , "Fashion expert" .)