Town with Welshman spreading danger: extremely canny about it (6,6,4)

I believe the answer is:

welwyn garden city

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'town with welshman spreading danger extremely canny about it' is the definition.
I can't judge whether this definition defines the answer.

'spreading danger extremely canny about it' is the wordplay.
'spreading' becomes 'welwyn' (I can't explain this - if you can you should give a lot more credence to this answer).
'extremely' suggests removing the centre (only the extremes of the word are used).
'about' indicates anagramming the letters.
'canny' with its middle removed is 'cy'.
'danger'+'cy'='dangercy'
'dangercy' with its letters mixed up with 'it' gives 'gardencity'.
'welwyn'+'gardencity'='WELWYN GARDEN CITY'

Can you help me to learn more?

(Another definition for welwyn garden city that I've seen is " "New Town" of the 1920s".)

I've seen this clue in The Times.

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