On having cracked puzzle, enough to demonstrate my point (3,7)
I believe the answer is:
for example
'to demonstrate my point' is the definition.
(phrase said before citing an example)
'on having cracked puzzle enough' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'having cracked' is an insertion indicator (inserted letters crack into others).
'puzzle' becomes 'fox' (synonyms).
'enough' becomes 'ample' (I've seen this before).
're' put inside 'fox' is 'forex'.
'forex'+'ample'='FOR EXAMPLE'
(Other definitions for for example that I've seen before include "Say" , "By way of illustration" , "Speed" .)