Hairdresser placing pen on catalogue (7)
I believe the answer is:
stylist
'hairdresser' is the definition.
(I know that hairdresser can be written as stylist)
'pen on catalogue' is the wordplay.
'pen' becomes 'sty' (both can mean an animal enclosure).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'catalogue' becomes 'list' (a catalogue is a list of items).
'sty'+'list'='STYLIST'
'placing' is the link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for stylist that I've seen before include "One who shapes or designs, say hair-do" , "Good writer" , "Clothes designer; hairdresser" , "Elegant author" , "(Hair) designer" .)