He had necklaces made; they are totally different (5,3,6)

I believe the answer is:

chalk and cheese

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'he had necklaces made they are totally different' is the definition.
The definition suggests a singular noun which matches the answer.

'he had necklaces made' is the wordplay.
'made' indicates anagramming the letters.
'he'+'had'+'necklaces'='hehadnecklaces'
'hehadnecklaces' is an anagram of 'CHALK AND CHEESE'.

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I've seen this clue in the Sydney Morning Herald.

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