Social conventions further south (5)

I believe the answer is:

'social conventions' is the definition.
(I've seen this in another clue)

'further south' is the wordplay.
'further' becomes 'more' (synonyms).
'south' becomes 's' (abbreviation).
'more'+'s'='MORES'

(Other definitions for mores that I've seen before include "of St Thomas's" , "Social customs of a group" , "Fundamental values of a group" , "Conventions, manners" , "Way of life" .)

I've seen this clue in the Evening Standard.

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