Chat with comparatively dishy workman (3,6)

I believe the answer is:

gas fitter

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'workman' is the definition.
(gas fitter is a kind of workman)

'chat with comparatively dishy' is the wordplay.
'chat' becomes 'gas' (informal term meaning to chat).
'with' is a charade indicator (letters next to each other).
'comparatively dishy' becomes 'fitter' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'gas'+'fitter'='GAS-FITTER'

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I've seen this clue in The Independent.

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