Group prepared to defend record time (6)
I believe the answer is:
septet
'group' is the definition.
The answer is an example.
'prepared to defend record time' is the wordplay.
'prepared' becomes 'set' (set up or ready).
'to defend' is an insertion indicator.
'record' becomes 'EP' (abbreviation for extended play record).
'time' becomes 't' (abbreviation).
'ep'+'t'='ept'
'set' enclosing 'ept' is 'SEPTET'.
(Other definitions for septet that I've seen before include "Group of seven players" , "A set of seven" , "Heptad" , "Several players" , "Seven-piece band" .)