One Channel port that's in Hampshire (7)

I believe the answer is:

andover

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'in hampshire' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'one channel port' is the wordplay.
'one' becomes 'an' (an apple is one apple).
'channel port' becomes 'Dover' (English Channel port).
'an'+'dover'='ANDOVER'

'that's' is the link.

Can you help me to learn more?

(Other definitions for andover that I've seen before include "Town in Hampshire" , "Hants town" , "New town development" .)

I've seen this clue in the Evening Standard.

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