Happened to have been round about autumn (8)

I believe the answer is:

befallen

I'm a little stuck... Click here to teach me more about this clue!

'happened to' is the definition.
('befall' can be a synonym of 'happen to')

'been round about autumn' is the wordplay.
'round' indicates putting letters inside.
'about autumn' becomes 'fall' (synonyms. I am not sure about the 'about' bit.).
'been' placed around 'fall' is 'BEFALLEN'.

'have' is the link.

Can you help me to learn more?

(Other definitions for befallen that I've seen before include "(Having) happened to (someone)" , "Came to pass" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.