New unit established by Welsh woman in African city? (8)

I believe the answer is:

tunisian

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'in african city?' is the definition.
(relating to Tunis)

'new unit established by welsh woman' is the wordplay.
'new' indicates anagramming the letters.
'established by welsh woman' becomes 'sian' (I can't explain this - if you can you should believe this answer much more).
'unit' with letters rearranged gives 'tuni'.
'tuni'+'sian'='TUNISIAN'

Can you help me to learn more?

(Another definition for tunisian that I've seen is " North African native".)

I've seen this clue in The Telegraph.

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