Heading north, top-class coach skirts Polish residential area (8)
I believe the answer is:
suburbia
'residential area' is the definition.
(suburban area)
'heading north top-class coach skirts polish' is the wordplay.
'heading north' says the letters should be written backwards.
'top-class' becomes 'ai' (resembles Ab, informal term for top quality).
'coach' becomes 'bus' (synonyms).
'skirts' is an insertion indicator (skirt can mean to go around).
'polish' becomes 'rub' (polish meaning rub to make shiny).
'ai'+'bus'='aibus'
'aibus' placed around 'rub' is 'aibrubus'.
'aibrubus' backwards is 'SUBURBIA'.
(Other definitions for suburbia that I've seen before include "Pet Shop Boys song" , "Residential area away from city centre" , "Outer city regions" , "Residential district on a city's outskirts" , "Residential districts on the outskirts of a city" .)