Club supporters of course part of the furniture (7)
I believe the answer is:
settees
'furniture' is the definition.
(I've seen this before)
'club supporters' is the wordplay.
'club' becomes 'set'.
'supporters' becomes 'tees' (tees support golf balls).
'set'+'tees'='SETTEES'
'of course part of the' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for settees that I've seen before include "Long indoor seats" , "furniture" , "Sofas" .)