Campanologist, initially late, gets duplicate (4,6)
I believe the answer is:
dead ringer
'duplicate' is the definition.
(I've seen this in another clue)
'campanologist initially late' is the wordplay.
'campanologist' becomes 'ringer' (I've seen this before).
'initially' means one lot of letters go next to another.
'late' becomes 'dead' (similar in meaning).
'ringer' put after 'dead' is 'DEAD-RINGER'.
'gets' is the link.
(Other definitions for dead ringer that I've seen before include "Lookalike" , "that might explain silent phone call?" , "double" , "Likeness" , "Someone who looks very like another" .)