Repair of concrete fencing not everyone wanted at first (7)
I believe the answer is:
renewal
'repair' is the definition.
(renewal is a kind of repair)
'concrete fencing not everyone wanted at first' is the wordplay.
'concrete' becomes 'real' ('real' can be similar in meaning to 'concrete').
'fencing' is an insertion indicator (to fence can mean to contain or put a limit round).
'at first' suggests taking the first letters.
The first letters of 'not everyone wanted' is 'new'.
'real' placed around 'new' is 'RENEWAL'.
'of' is the link.
(Other definitions for renewal that I've seen before include "Extension of validity" , "one of the library's services" , "Continuance" , "Action of restoration" , "Act of refreshing" .)