Smack joint next to Kent town (7,8)

I believe the answer is:

knuckle sandwich

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'smack' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'joint next to kent town' is the wordplay.
'joint' becomes 'knuckle joint' (joint in the hand).
'next to' is a charade indicator (letters next to each other).
'kent town' becomes 'Sandwich' (town in Kent).
'knuckle'+'sandwich'='KNUCKLE SANDWICH'

Can you help me to learn more?

(Other definitions for knuckle sandwich that I've seen before include "piece of pork between slices of bread" , "Bunch of fives" , "Punch in mug" , "Slug" , "hit" .)

I've seen this clue in The Telegraph.

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