Chap left Charlie with Penelope briefly, and first date occurred! (8)
I believe the answer is:
happened
'occurred' is the definition.
('happen' can be a synonym of 'occur')
'chap left charlie with penelope briefly and first date' is the wordplay.
I cannot quite see how this works, but
'chap' could be 'pen' and 'pen' is located in the answer.
'first' could be 'a' (first letter of the alphabet) and 'a' is located in the answer.
'date' could be 'd' (common abbreviation eg in DOB, date of birth) and 'd' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for happened that I've seen before include "Occurred" , "Took place" , "Came to pass" .)