Kochez vocals upset old guy from Prague (12)

I believe the answer is:

czechoslovak

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'old guy from prague' is the definition.
I can't tell whether this definition defines the answer.

'kochez vocals upset' is the wordplay.
'upset' indicates an anagram.
'kochez'+'vocals'='kochezvocals'
'kochezvocals' anagrammed gives 'CZECHOSLOVAK'.

Can you help me to learn more?

(Another definition for czechoslovak that I've seen is " Old European".)

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

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