Seemingly very amused having fixed match? (4,6)

I believe the answer is:

bent double

'seemingly very amused' is the definition.
(bent over laughing)

'fixed match?' is the wordplay.
'fixed' becomes 'bent' (both can mean dishonest or corrupt).
'match?' becomes 'double' (double can mean a match or copy).
'bent'+'double'='BENT DOUBLE'

'having' acts as a link.

(Another definition for bent double that I've seen is " hunched over".)

I've seen this clue in The Times.

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